Two veteran FBI agents were killed and three others wounded Tuesday morning around 6 a.m. when a gunman opened fire as the agents attempted to serve a search warrant at an apartment in Sunrise, FL, as part of a child-pornography probe.

The gunman, not yet identified by the FBI, is believed to have monitored the approach of the agents with a doorbell camera and ambushed them through the unopened door with a rifle, law enforcement sources told the Miami Herald.

“There are several huge holes in the door going outward,” one law-enforcement official said.

FBI Director Christopher A. Wray identified the slain FBI agents as Special Agent Daniel Alfin, 32, and Special Agent Laura Schwartzenberger, 33.

Their suspected killer reportedly ended his own life during a standoff with law enforcement.

FBI spokesman Jim Marshall confirmed in an email to Local 10 that three agents were also wounded, two of whom were transported to a hospital in stable condition. The third injured agent was not hospitalized.