During the 8-year war between Iran and Iraq Al-Maliki fled from Iraq to Iran - like a million other iraqi shi ites.
He was recruited by the iranian Pasdaran, the Revolutionary Guards, and became a member of this guard-unit of the iranian military forces.
Like german communists in WW2, wo were cooperating with soviet military, Al Maliky then was used for propaganda operations on the front - trying to convince iraqi shi ite soldiers to lay down their wepons or by interrogating iraqi POW´s in order to defect to the iraqi shi ite forces fighting on iranian side.
When in Iraq the new democratic election system was introduced more than 95% the iraqi shi ites voted like they were ordered by their spiritual leader Grand-Ajatollah Sistani (an iranian, by the way).
And because the shi ites are 60% of the iraqis they got the majority in the parliament. Then it was also a wish of Sistani and the mullahs in Iran that Al Maliki should be the president of Iraq - and so he became it.
His first visit was to Iran where he thanked President Ahmadinedjad for the iranian help and blamed the foreign occupation forces for the problems in Iraq.
That was years ago and shown in TV - even western TV.
During the next year Al Maliki systematicly kicked out sunnite high ranking officers out of the new iraqi army and police, replacing them with shi ites. So this new "iraqi" army/police becomes a shi ite instruments, which is also cooperating with the shi ite militias - like in Basra or like during the execution of Saddam, where one of the shi ite militias replaced the execution team and performed the hanging of Saddam.
If the execution file still exists in youtube you can hear the executioners of Saddam, how they blame him for the death of of one shi ite Ajatollah and kill him before he could finish his prayer.
So why anyone should be surprised with the actual behavior of Al Maliki ?
This all happens since he was made president.