CHICAGO (CBS) — A new twist in the case of an elderly man murdered on his way to dialysis earlier this month. Investigators now say his own grandson pulled the trigger.

The 19 year-old not only lived with his grandfather, but also shared a name with his grandfather.

William D. Strickland was arrested Thursday and charged late last night with the death of his 72 year- old grandfather. The teen is facing First Degree Murder and Armed Robbery charges and was denied bond.

March 2, police say two men ambushed the elder William Strickland, in the gangway of his home near 95th and King Drive, and shot him several times.

Strickland died lying outside his house. His wallet was also stolen.

The grandfather was on his way to dialysis, like he did every Saturday morning around 3:30.

CBS 2’s Courtney Gousman talked to Strickland’s daughter that day, who we now know, is also the mother of the man arrested in this murder.

Lesley Strickland felt then, her father’s death was calculated by someone who knew his habits.

“I do not feel as though it was a robbery. I feel as though it was up close and personal because they knew the exact time he was coming out the house,” said Lesley Strickland.

Lesley Strickland also told CBS 2, her son and her father’s wife were home at the time of the murder.

Police say Strickland did not act alone, and they’re still searching for a second offender.