CLAYTON, Mo. – The trial continues for the man accused of killing St. Louis County police officer Blake Snyder.

Trenton Forster is charged with first-degree murder in the 2016 death of officer Snyder.

In its fourth day – one of the jurors dropped out and was replaced. Trenton Forster’s grandmother and aunt took the stand Thursday morning. Both revealed Forster had anger problems even as a young child.

Forster’s aunt said Trenton and his dad were “abnormally close, almost obsessive.”

His grandma said he [Trenton] kept thinking someone was after him.

Prosecution: “You’ve placed a lot of blame on Bill [Forster’s dad] here today, is that fair to say?” prosecution asked. 

“Yes,” Forster’s aunt said.

“Did Bill pull the trigger and murder officer Snyder?” Prosecution asked.

“No,” replied Forster’s aunt.

5 On Your Side's Brandon Merano was in the courtroom and said there were gasps of 'wow' as Forster's aunt left the stand. 

The defense called Forster’s brother to the stand. He testified Trenton had anger problems when he was younger that were “more than a normal tantrum.” The brother said Trenton would sleep in his closet growing up and that it was a “pretty permanent thing for quite some time.”

Forster’s brother has been previously arrested on a felony drug possession charge.

The prosecution asked Forster’s brother if he would describe Trenton as manipulative and he replied, “yep.” He was also asked if Trenton was given opportunities to get help and he said, “yep.”

A paramedic testified in court that in the ambulance Forster told her if he would have known he [Blake Snyder] was a cop he wouldn’t have shot him.

Forster's mom and dad took the witness stand Thursday afternoon. 5 On Your Side’s Brandon Merano said there was an explosive exchange that happened as soon as the prosecution started their cross-examination with the dad.

Forster's dad said he saw Trenton the day before the shooting occurred at 2 p.m. and he called the police to let them know Trenton was “incoherent” and said he was worried he was a danger to himself and others.

After reviewing the call log the prosecution said Forster's father didn't say any of those things and the prosecuting attorney said: "We wouldn't be here if you said he was suicidal, drunk or had a weapon."

DAY 3

The day St. Louis County police officer Blake Snyder was shot he was most likely just trying to help the teen on the other end of that gun. That's how Trenton Forster's lawyer sees it and he even admitted his client pulled the trigger. But he's trying to convince a jury not to send Forster to prison for the rest of his life.

The fight in the downtown Clayton courtroom is when Forster shot Snyder whether it was first-degree murder or second-degree murder—premeditated or not.

Depending on how the jury sees it, Forster could spend the rest of his life in prison or go free before he's 50.

His attorney wants the jury to consider his mental health.

In the days leading up to the murder, a forensic psychologist for the defense team said Forster was "off the charts" manic and not thinking rationally.

Psychologist Patricia Zapf was hired by Forster’s defense team to evaluate his mental health. Diagnosed with bi-polar disorder, Zapf said Forster was paranoid, angry and obsessed with buying a gun—and unable to consider the consequences of his actions.

Prosecutors said he was planning.

In addition to trying several times to buy a gun, they point to social media posts, phone calls and text messages where Forster said he wanted to kill, writing "f--- the police"..."I want to take them out," they said in court.

Zapf, the psychologist for the defense team, said these were the rantings of a teenager who couldn't think clearly, which was complicated by his history of getting high and drunk since he was around 12 years old.

Based on interviews with Forster and some of his family members, Zapf also testified to what she called a "chaotic" home life where his mother would “scrub him raw” when he ate meat because she thought it was dirty. His father was addicted to opioids.

Thursday, Forster’s defense team is expected to call members of his family to the stand when the trial continues.

DAY 2

On Tuesday morning, prosecutors presented evidence to build their case against Forster. Drug paraphernalia and a .22 caliber AK-47 were found in Forster’s trunk at the scene of the shooting. Forster looked down and shook his head when the evidence was presented

He turned and looked at the courtroom when photos of Forster’s car with bullet holes were presented to the jury. Forster looked down and put his head in his hands.

Blake Snyder’s widow, Elizabeth, and the rest of the Snyder family were very emotional when x-rays of the fatal bullet wound were shown in court.

The doctor who performed the medical examination told the prosecution the manner of death was homicide.

Later in the day, tweets, texts and Google searches were entered into evidence by the prosecution and defense.

The digital footprint presented by prosecutors included numerous violent threats including texts that read:

“I’m going to kill people”

“I’m bout to kill everybody for real, everybody about to know how much anger I got”

“I need a pistol very very very bad, I’m in a bad situation”

“I used to just dream about gunning motherf---ers, when I’m 18 I’m going to get a semi auto AK and kill all of them. Not the innocent ones just the ones who put me in this situation”

The search history presented by prosecutors showed he searched multiple times for ways to get a gun and what he could legally do when he got one. The searches included:

“Top 10 things you need to know about federal gun law”

“Could I walk up the street with an AK-47 legally?”

5 On Your Side's Brandon Merano said Forster slouched way down in his chair and almost looked asleep when the prosecution presented search history evidence.

The defense showed a different digital history, including Google searches for ways to overdose.

The defense showed tweets in which Forster seemed to reach out for help.

“Pray for me please” July 24, 2016

“Life is a big S---hole at the moment” Aug. 8, 2016

“I’m dying on the inside and nobody really gives a f---” Sept. 22, 2016

Forster's posts on social media shown by the prosecutor were violent and cryptic. His tweets included:

“I want f--- the police carved into my grave”

“My anger problem gonna have me catch a body one day”

“Nobody controls me I’m gonna do whatever the f--- I please,”

Just two days before the fatal shooting, Forester posted on Snapchat pointing a gun at the camera.

The defense showed texts from Forster's dad to his son in the days just before the shooting.

A few weeks before the shooting, Forster received a text from his dad with a picture and the text "This picture is from the days you were drug free, can you honestly tell me you are happier now than you were then?”

And in the days before the shooting, Forster's dad sent him a text saying he was not allowed and the family's home. About 12 hours before the shooting, Forster received a text from his dad saying “I already told you, you are not allowed at my house until you are clean,”

5 On Your Side's Brandon Merano also learned Forster got his 9mm handgun from a private seller.

According to court testimony, a woman traded the gun to another man to borrow a bobcat tractor.

That man then met Forster and sold him the gun.

The final piece of significant information came when we learned Forster bought bullets illegally from a Shrewsbury Walmart.

According to Missouri law, you have to be 21 to buy handgun ammunition from a licensed dealer.

DAY 1

Testimony began at 9 a.m. on Monday. If convicted, he could face life in prison without the possibility of probation or parole.

Prosecution in the trial of Forster claims Forster said, “I have a gun f--- it shoot me.”

After shooting Snyder on Oct. 6, 2016, Forster was shot by the second officer on scene and taken to the hospital.

The defense attorney for Forster said he started using alcohol in the sixth-grade and has had a problem with drugs and bipolar disorder. He claimed this played a role in the shooting of officer Snyder.

“You’re going to find him guilty of murder, but I ask that you don’t find him guilty of murder in the first degree,” Forster’s Defense Attorney Stephen Reynolds said.

Prosecutors asked Elizabeth Snyder if she remembered Oct. 6, 2016, she emotionally replied, "Yes, it is the day Blake was killed."

Following that exchange, she got up from the witness stand glanced at Forster and took her seat.