ST. LOUIS — Six people were shot and killed in St. Louis over a 24-hour period Sunday into Monday morning. The homicides happened at five scenes and five of the victims were shot and killed in vehicles.

St. Louis Police Chief John Hayden described shootings as “very alarming.”

“When six occur in 24 hours, we’re very concerned,” he said, adding that the crimes stretch their resources, but detectives are working diligently to gather details and bring justice.

Chief Hayden said drugs were involved in four of the five homicide scenes, and there were drugs found at the scene of two of the incidents.

At this time, Chief Hayden believes two of the shootings are related.

READ MORE: Sister wants answers after twin was 1 of 6 found dead over the weekend

The crimes started Sunday morning.

At 7:21 a.m., a call went out for a car crash in the 4200 block of Evans in the Vandeventer neighborhood near the Central West End. Crews found Whitney Whitman, 33, dead inside a car with a gunshot wound.

At 11:46 a.m., Louis Bishop, 22, was found dead in a vacant lot the 3000 block of Marcus Avenue. He was shot several times, police said. A previous version of this story stated Bishop was found dead in a vehicle, but updated information from police changed the location from inside a vehicle to in a vacant lot.

At 12:40 p.m. and half of a mile away, a woman was found dead in a vehicle with apparent gunshot wounds in the 2800 block of Taylor Avenue, police said. She has been identified as Tamella Buchanan, 25.

Family members confirmed with police that Buchanan and Bishop were in a relationship. At this time, investigators do not know whether their relationship had anything to do with their deaths, Chief Hayden said.

RELATED: 2 women, 1 man found shot to death Sunday

At 8:41 p.m. Sunday, police responded to a shooting in the 900 block of Canaan. They found Teon Buchanan, 23, dead in a vehicle with gunshot wounds. When asked whether Buchanan was related to Tamella Buchanan—who was killed eight hours earlier—Chief Hayden said they don’t believe the shootings are related, and they haven’t determined whether the man and woman are relatives.

A short time later, police responded to another shooting in the 900 block of Harlan, which is two blocks from where Teon Buchanan was shot. Officers found a 25-year-old man with gunshot wounds to his hand and leg. He survived and was arrested, along with one other man. An investigation found Buchanan and the arrested men got into an argument inside a vehicle, which ended in a shooting.

At 6:26 a.m. Monday, police responded to a call for suspicious people inside a vehicle just north of Delmar, near the Central West End. Officers arrived to the 700 block of North Euclid to find a man and woman shot to death inside a car. They've been identified as Kristal Byrd, 38, and Anthony McMillian, 40.

To see an interactive map of the incident locations, click here.

St. Louis now has 130 homicides this year, which is down from the 149 homicides at this time last year. About 50 percent of the city’s homicides are drug related, Chief Hayden said, with marijuana and heroin being the main concerns.

When asked what’s being done to stop the violence, Chief Hayden said his detectives are working around the clock, but they need help from the public.

“We are always seemingly begging for information from others. We could solve all of them with the right information. When people are holding on to information and sharing it amongst themselves it’s always very difficult to bring these investigations to the conclusion we would like,” Chief Hayden said, urging anyone with information to call CrimeStoppers at 1-866-371-8477.

“Six in 24 hours is additionally concerning and that’s why the chief is having a press conference today,” said St. Louis Mayor Lyda Krewson. “It does not seem like these are random situations, and they are doing everything possible in order to do the investigation and solve these.”

Family members are often left struggling in the wake of violent crime. One place where they can find help is the Missouri Crime Victims' Compensation Fund. It supports violent crime victims and their families with up to $25,000. Click here for more information.