Under Cover by Amy Lane

For Judson Crosby, the transfer to the elite law enforcement branch of the SCTF is a great escape from the death sentence he earned as a whistle-blowing patrol officer. Calix Garcia, the fierce new guy, makes a perfect partner, catching bad guys while minimizing collateral damage. Crosby loves working with him.
Of course, he’d also love to work him over in a totally different way.
Garcia has waited his whole career for a solid, dependable partner like Crosby. But after six months fighting crime together, he’s done fighting their attraction.
Their coming together promises to be everything they need… until a threat from Crosby’s past comes back to haunt not just him, but their entire team.
When Crosby goes undercover to keep them safe, Garcia is frantic with worry. One false move could get Crosby killed and Garcia exposed. But they have to fight their way clear, because hiding your lover under the cover of darkness is no way to live. Crosby and Garcia will risk everything for the chance to live their lives in the light.