City police are looking into whether two recent homicides might be connected, with the common thread a borrowed vehicle, according to three sources familiar with the investigation.

On Jan. 10, police found the body of Darel Alston, 38, inside a vehicle in East Baltimore. The passenger door was open, with Alston, suffering from gunshot wounds, slumped in the seat.

Law enforcement sources, who requested anonymity because they were not authorized to discuss the investigation, say police believe Alston lent his vehicle a week earlier to the people responsible for the killing of Marcal Antwan Walton Sr., 33, who became the city's first homicide victim of the year Jan. 3 when he was abducted from a home in Southwest Baltimore and was found a short time later shot to death in an alley north of Mondawmin Mall.

Police found the abandoned vehicle after Walton's death and traced it to Alston. Police learned that Alston had been trying to get out of town, fearful that Walton's killers might come after him, the sources said.

Though the two killings could prove to be unrelated, the vehicle link highlights the interconnected nature of much of the city's violent crime. Alston and Walton had criminal records, and police say drugs might have played a role in the killings.

Walton had a long record of drug arrests and pleaded guilty in 1997 to a drug distribution charge. He was convicted in federal court as a felon in possession of a handgun, receiving 37 months in prison.

He also unwittingly played a key role in the investigation into the fatal shooting in February 2000 of Baltimore County police Sgt. Bruce A. Prothero, who was moonlighting as a security guard at a jewelry store. Walton was under surveillance as part of a theft ring when a man called, offering to sell jewelry stolen during the robbery in which the officer was killed. Police traced the call and identified a suspect.

But in an obituary posted on the Web site of the funeral home where his services were held last week, Walton, known as "Henry," was remembered as a family man who had a passion for cars and "enjoyed skating, playing cards, the board game Sorry, watching movies at home and the 'Young and Restless' with his Grandma." He had three children.

A city officer is being investigated for failing to take a missing-person report from Walton's family. The officer is accused of telling the family that Walton was "locked up" when detectives were investigating his death a day earlier.

Alston, then 19, was convicted of robbery in 1990, in an incident that left a Baltimore tavern owner dead. Alston admitted hitting Joseph Gerber, 63, in the head with an aluminum baseball bat, but was acquitted by a Baltimore County jury of murder. The judge believed that Alston was partly responsible for Gerber's death and sentenced him to more than 26 years in prison on robbery charges.

"I was locked up in 1989, forced to confess to crimes I didn't commit as well as the ones I done. I was 18 years old then and on drugs," Alston wrote to then-Gov. Robert L. Ehrlich Jr. in a 2007 appeal asking that he be released.

Alston said he had received graphic arts training, completed his high school and college degrees, and written a book used in a "scared straight" program, according to a copy of the letter. He was released from prison in August 2009 on mandatory release.

Attempts to reach relatives of either Alston or Walton by phone were unsuccessful.