Later on Sunday, Halfacre was found and arrested with the help of SWAT, police said.
Halfacre is being held on preliminary murder, attempted murder, and robbery charges, according to the Marion County Jail records. A hearing had not been set as of Monday.
It was not clear if Halfacre has obtained legal representation at this time.
IMPD Chief Randal Taylor and Deputy Chief Craig McCartt said during a press conference on Monday that the first shooting was related to domestic violence.
"It is evident from this weekend's tragedy that domestic violence affects both adults and children," Taylor said. "Domestic violence is real."