Police said Robinson was a suspect in the shooting, which they said appeared to have stemmed from a domestic dispute.
Police identified the other two as Andrew Scott Hoffman, 27, of Glen Burnie, a Baltimore firefighter, and Marie Leanne Edith Hartman, 26, also of Glen Burnie.
Police said Robinson had a relationship with Hartman, and the three knew each other.
The incident occurred about 1:35 a.m. in Hoffman’s home, in the 1100 block of Armistead Street, Anne Arundel police Lt. T.J. Smith said.
He said that when officers arrived at the single-family home, they found the two men and the woman with gunshot wounds. All three were pronounced dead at the scene.
Hoffman was recognized in July by the Anne Arundel County police for helping get a 3-year-old child safely back to his parents after spotting the toddler wandering on a street about a mile from his house.
Baltimore Fire Chief Jeffrey Segal said in a statement that Hoffman was a third-generation member of the department and had served since 2006.
“Our hearts are saddened,” Segal said in a statement on the department’s Facebook page.
The Baltimore City Firefighters Union Local 734 said in a statement that Hoffman was assigned to Engine Co. 14, one of Baltimore’s busiest units.
“Andrew was a loving son, brother and uncle to his family,” the statement said.
Peter Hermann contributed to this report.