A man detonated a suicide car bomb outside of a Baghdad police academy Sunday as recruits were leaving the building, police said.
The bomb exploded as a group of police recruits were leaving the academy, wounding at least 21 others, reports said.
No one has claimed responsibility, but officials believe it is al Qaeda related, according to CNN.com.
The bomber waited for the group to leave the premises and enter the street, in which he drove his car next to them before it exploded.
Academy officials said the recruits had just finished a two-week training program.
In a separate incident, four people were gunned down at a house north of Baghdad in the Diyala province.
The victims were mainly ex-al Qaeda soldiers who have become targets for attacks recently. The United States has supported these Sunni Arab fighters who are helping to reduce violence in the region.