ST. LOUIS — Sierra Schlemmer says her father was a happy go lucky kind of guy who loved to take pictures and was inseparable from her and her sister.

"We always took pictures. He was just a very caring person. He was a good, goof-ball kind of guy who was always the life of the party," said Sierra.

Schlemmer says she last saw her father on October 26th when she celebrated her 18th birthday.

"He gave me a birthday present and everything. I hugged him and I told him that I loved him," said Sierra.

She couldn't believe what happened to her dad six days later.

Witnesses told police Mark Schlemmer first left a Halloween party at City Museum.

A short time later, Sierra said her dad, his friend and a young woman left an after-party at Europe nightclub near 15th and Washington Avenue, hopped in his friend's car and were about to leave when a guy pulled up in a white Malibu with a gun.

RELATED: 'He loved his girls' | Friends help daughters of man killed on Halloween night near Washington Ave.

RELATED: Man shot near popular area of Washington Avenue after Halloween night dies

RELATED: Man in critical condition after shooting near City Museum

"It happened so fast. He shot through the driver's side window. The bullet shot passed him and hit my dad in his head. My father was sitting in the front passenger seat. It was horrible. It's just so crazy, and I think my brain is still trying to process that it really happened," said the grieving daughter.

Witnesses told police after the shooting, the gunman hit two parked car, jumped out of his vehicle and took off on foot.

As she prays for his arrest, Sierra Schlemmer finds comfort knowing her dad was an organ donor.

"It's really nice knowing that he's gonna be saving lives and his heart will actually be beating in someone else that I should be able to meet one day," said Sierra Schlemmer.

Police are reviewing surveillance video from the night of the shooting.

Meantime, Mark Schlemmer's family is now preparing a memorial service for him.

More local news:

RELATED: Another batch of cold air arrives Thursday, and it could bring some snowflakes

RELATED: MSHSAA: McCluer North football program used an ineligible player for most of its season

RELATED: Ready or not? St. Louis overdue for a major earthquake 'tomorrow or anytime'