Courtney Meeks was killed Feb. 26 while on duty at a CVS store on Schaefer.
Police Chief James Craig said a Crime Stoppers tip led them to the first suspect. From there, through the execution of a search warrant, they took the second suspect into custody.
Craig said the second suspect has made a "full confession."
On Wednesday afternoon, Craig said police were still on the hunt for a third person, 20-year-old Jamare Lanell Rucker.
"He should be considered armed and dangerous," Craig said. "Jamare needs to turn himself in, but I anticipate he'll be arrested soon."
Rucker was taken into custody just hours later.
Copyright 2014 by ClickOnDetroit.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.