Mexico, a wave of bomb attacks has hit the Mexican state of Tamaulipas where police are investigating the mass killing of 72 migrants. Four devices exploded separately in Tamaulipas on Sunday injuring at least 17 people. The explosions appeared to target places connected with the probe into the migrant killings. Police are still searching for a prosecutor involved in the case who has been missing for several days. Reports say three homemade bombs were detonated in the city of Reynosa in the north of the state on Saturday. One exploded close to a church where a memorial mass was being held for the migrants, whose bodies were found at ranch earlier this week. Two other devices were detonated near the morgue where some of the victims' bodies were being held.The blast injured a police officer and a civilian and destroyed the guard's hut in front of the building, a police source told the AFP news agency. Reports said that on Friday, two bombs exploded in the state capital, Ciudad Victoria, targeting a television station and the offices of the transport authorities. There were no reported injuries. Police have said the attacks are probably the work of the Zetas drug cartel, which has also been blamed for the migrants' deaths.