MARIETTA - The first officer on the bloody scene where Marlisa Wells, 16, was killed, testified Thursday that it was "one of the worst and most gruesome scenes" he had ever been to in his career in law enforcement.

Thursday was the second day of the trial of Mathew Wilkins, 21, who faces felony murder, malice murder, aggravated assault and aggravated battery charges for the January 2008 killing of his love interest, Marlisa Wells. If found guilty, Wilkins faces life in prison rather than the death penalty, his attorney said.

Austell Officer Roy Collar said he responded to a 911 call on Jan. 19, 2008, which led him to the home of Charlotte and Marvin Wells at Newnan Circle in Austell. There, Collar said he saw blood splatters and smears on the basement stairs, the stairway railing, the carpet outside the door leading to the back patio, as well as the patio, and on furniture in the basement, on the walls outside the basement bathroom, and throughout the bathroom where Marlisa Wells was found by her grandparents that afternoon upon returning from a funeral.

"There was blood everywhere, and she had a severe head injury and a bent fork sticking out of her back. I checked her vitals, and she was cold to the touch," Collar said.

Prosecution presented the jury with three large knives found in the trash can of the basement bathroom, a knife blade found under Marlisa Wells' body, a toilet tank lid with a broken corner and blood splatters, and a fork bent backwards at a 90 degree angle, which prosecutors said the Cobb medical examiner removed from Marlisa Wells' body.

After spending a few hours with the "distraught" grandparents and Charlotte Wells' brother, Collar said he joined an investigative team to search Wilkins' parent's Douglasville home, where Wilkins was staying for the weekend.

"I noticed an attic with pull-down stairs, so I went up there and at first it looked typical, with a few luggage suitcases and that sort of thing. But then I noticed a wad of clothes behind the heating and air unit, and upon further inspection, found a pair of tennis shoes wrapped up in the clothes, and one shoe had what I thought to be blood on one of the shoestrings," Collar said.

Prosecution said during opening statements on Wednesday that the blood came back from the crime lab as positive for Marlisa Wells' blood.

Marlisa Wells' brother, Eric Wells, now 15, said Wilkins had a history of aggression towards his sister.

"One day, she was in her room, arguing with him over the phone, and I could hear him screaming through the phone," Eric Wells said. "I heard him cursing at her and calling her names, so I got on the phone and told him not to talk to her like that, and told her she shouldn't talk to him."

Eric Wells also said he came home from school one day to find his sister reading a MySpace message from Wilkins.

"I saw that she was reading a message from Mathew that said something about, 'gonna kill you.' I told her to stop talking to him because that was not cool, but I don't think she did," Eric Wells said.

Marlisa Wells' cousin, Ryan Gordon, also said Marlisa Wells would confide in him about Wilkins, and though he had never met what Marlisa Wells called her "boyfriend," she talked about him often.

"She was sick and throwing up and said she thought she was pregnant and told (Wilkins) a week before, but he said he wasn't ready to have a child. That weekend, she said she was going to sneak him in and talk to him about it," Gordon said of the weekend Marlisa Wells died.

He also said Marlisa Wells often called Wilkins "her world."

Marlisa Wells' mother, Erica Young, also testified Thursday. She said she met Wilkins once when he took her daughter out in July 2007, before he left for college in Tifton, but that it took her daughter promising they were just friends before she allowed it.

"At the end of May, she asked if he could take her out for her birthday, and I said OK, but he never called and didn't talk to her for two weeks. She cried very strongly, and said he was her boyfriend," Young said.

But at Thanksgiving, Young said Marlisa Wells brought up Wilkins again, saying she was still seeing him.

"She loved him, and said he was her soul mate," Young said, through tears.

Wilkins' defense attorney Vic Reynolds said a neighbor told an Austell police officer conducting a neighborhood canvas that Marlisa Wells had a history of sneaking other males into her grandparents' home, known by their nicknames of A-Rod and T.C., though Reynolds said he was not sure if the neighbor or the officer would testify.

Reynolds said Wilkins retained him and his other defense attorney privately.

The trial resumes today in the chambers of Cobb County Superior Court Judge LaTain Kell at 9 a.m.