ADDISON (CBSDFW.COM) – A 30-year-old man is behind bars, charged with first degree felony murder for the slaying of an 82-year-old woman found dead in her wheelchair.

Addison police arrested Walter Portillo in the death of Joan Mulcahy outside her apartment in north Addison on the evening of July 1, 2019.

Walter Portillo (credit: Addison Police Dept.)

In the Dallas County Jail since July 10, Portillo was arrested on unrelated charges filed by the Garland Police Department.

Quickly after the murder at 4820 Westgrove Drive, Addison Police obtained a sketch of Portillo based on information provided by a witness who saw a man lingering in the breezeway outside Mulcahy’s apartment before the attack. A witness who saw the sketch reported having been followed to her car by the same man a few blocks away shortly after the Addison Police and Fire Department responded to the original call. Addison Police obtained video of Portillo from surveillance cameras operated by two nearby businesses, identified him, and discovered that he already was in Dallas County Jail.

Addison detectives, along with a Texas Ranger, interviewed Portillo who admitted several times to killing Mulcahy.

Addison homicide investigation (credit: CBS 11 News)