Iraqi officials say a car bomb exploded outside a police crime lab in the northern city of Mosul Tuesday, killing two officers.
At least seven other people were wounded in the morning attack.
In a similar incident last month, a suicide bomber struck a police forensics lab in Baghdad, killing 22 people. A group affiliated with al-Qaida, the Islamic State of Iraq, claimed responsibility for that attack.
Also in Mosul Tuesday, a police official says gunmen opened fire on two Christian university students, killing one and wounding another.
On Monday, three bombings in western Iraq left one person dead, and wounded at least four others.
Some information for this report was provided by AFP and AP.