King County jurors deliberating a first-degree murder case involving a man accused of shooting his stepfather told a judge Friday they were unable to come to a unanimous decision.

The announcement from the jury came after less than a day of deliberations.

But Superior Court Judge Richard Eadie ordered jurors to keep going; their deliberations will resume on Monday, said defense attorney Tim Leary.

Zachary Collins, 21, is charged with first-degree murder in connection with the slaying of Glennis Parker in February. Parker was found dead in the driver’s seat of his GMC truck in a parking lot in the First Hill neighborhood.

Seattle police say that Collins and Parker got into an argument at Parker’s Central Area home on Feb. 9, about an hour before the slaying, and that someone from the home dialed 911 at 1:36 a.m. The line was disconnected without anyone speaking with dispatchers, though a fight could be heard over the line, charges said.

When a dispatcher called the number back, Parker’s wife answered and said there was no problem at the home, charges said.

After the fight, Collins left the home, but his mother, disabled stepbrother and Parker remained behind, charging documents said. Parker left the home a short time later and was found dead in his truck around 2:30 a.m.

A woman later told police that an upset man approached her at Pike Street and Terry Avenue on the morning of Feb. 9 and asked to use her phone to call his mother. The woman said that the man was crying and pacing. The woman said that she overheard the man say, “He did that to my brother!” and “I had to do it,” charges said.

Police later showed the woman a photo montage and she pointed out Collins, saying he looked like the man who used her phone, according to charging documents.

The Seattle Times: The Blotter