SALT LAKE CITY — Could a new witness and a piece of carpet from a vehicle provide answers as to how a Salt Lake mother of four died?

While Salt Lake police have been silent about their investigation into the death of 49-year-old scientist Uta von Schwedler, a newly released search warrant shows detectives are still actively investigating the case and are treating her death as a homicide.

The warrant, signed by a judge on May 9, was seeking "blood" and "any other trace evidence of the crime of criminal homicide."

On Sept. 27, 2011, von Schwedler's body was found in an overflowing bathtub in her house.

When she was removed from the tub, a knife was found under her body. Blood was found in her bedroom, on the edge of a sink and windowsill in the bathroom. The medical examiner listed her cause of death as drowning. But the manner of death "could not be determined." The autopsy noted that questionable injuries also found on her body "leave some question as to the exact scenario under which her death occurred."

Since her death, her oldest son, Pelle Wall, has engaged in a court battle with his father, John Brickman Wall, whom von Schwedler divorced in 2006 and was entangled in a bitter custody dispute over their four minor children at the time of her death.

Pelle Wall, who moved out of his father's house the day he turned 18,  is asking the state to also remove his three siblings from the house until the criminal investigation is completed.

In his petition filed in 3rd District Court, Pelle Wall said after his mother's death he was "so fearful for his physical safety around his father he has, on occasion, armed himself with knives."

On the morning of Sept. 27, the day von Schwedler's body was discovered by her boyfriend, Johnny Wall showed up for work with an eye injury. It was bad enough that co-workers told him to seek medical attention immediately, according to the search warrant.

Instead, Wall first took his car to Super Sonic Car Wash, 6500 S. State, at 8:30 a.m. to have it cleaned.

Salt Lake police detective Cordon Parks, who wrote the affidavit for the search warrant, said he thought it was "extremely suspicious" that Wall would get his car detailed before seeing a doctor.

Earlier this month, Salt Lake police went back to the car wash and interviewed an employee who had worked on Wall's car that day. It was the first time the employee had spoken to police, according to court records.

The employee told police he remembered Wall because he was "agitated and acted strangely," the warrant states. "Also, the car was clean and did not appear to need a total cleaning and detailing."

But Wall specifically pointed to 3-inch by 6-inch pink colored stain on the carpet behind the driver's seat, and told the person cleaning the car to "pay particular attention" to it, according to the warrant.

Above the stain on the carpet, the employee noticed a stain on the right rear seat cushion. He said it appeared something was put on that seat cushion and then dripped onto the carpet.

Police seized the seat cushion and carpet from the vehicle.

In the search warrant affidavit, Parks also writes that when police "interrogated" Wall on Sept. 28 and asked him where he was the night von Schwedler died, he replied by yelling, "I don't know where the (expletive deleted) I was!"

Investigators also noticed the injury to Wall's eye as well as scratches on his forearms. He claimed he had been scratched by the family dog. When asked if he had returned to von Schwedler's home after 8 p.m. on Sept. 26, he said he didn't know, the warrant states.

The new affidavit also provides more details about what police found in von Schwedler's house, 1433 E. Harrison Ave. (1370 South), on Sept. 27.

Von Schwedler had two knife wounds, one on her left arm and the other on her left leg. Detectives also found a "substantial" amount of blood on the comforter on her bed, "saturation blood stain" on her tank top, and a third "saturation blood stain" on von Schwedler's fitted bed sheet found hidden under a pillow, the search warrant states.

According to the autopsy report from the medical examiner, after von Schwedler's body was removed from the tub, a knife was found underneath her. Blood was also found on the edge of a sink and window sill in the bathroom.

"There were also incomplete footprints in blood on the floor of the residence leading away from the bedroom," the medical examiner's report states.

"Sharp force injuries" were found on von Schwedler's left wrist and left leg "not typical of self-inflicted wounds seen in the setting of suicide."

While the Utah Medical Examiner's Office noted the injuries could have been self-inflicted, it said: "They would also be consistent with defensive injuries sustained in the setting of a struggle with an assailant."

Another injury was discovered on her neck that could have been caused by a fall, "but could also be the result of applied force in the course of an assault," the medical examiner's report states.

A toxicology report also found elevated levels of Xanax in von Schwedler's system. Family members say von Schwedler never took Xanax and did not have a prescription for it. Wall, a pediatrician, was licensed to fill Xanax prescriptions and allegedly filled one for his mother, who lives out of state, but she did not receive it, according to court documents.

Salt Lake police on Thursday declined to talk about the investigation, saying the search warrant speaks for itself.

The custody hearing for Pelle Wall's siblings — ages 16, 13 and 11 — resumes Monday. Third District Juvenile Court Judge Charles Behrens has ordered those hearings to be closed to the public.

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