A Milwaukee man was charged Tuesday with bludgeoning to death his 12-year-old grandson after finding money missing from his wallet.

Andrez Martina, 54, used a sledgehammer, mallet and coat rack to beat Andre Smith II for up to 90 minutes, according to a criminal complaint obtained by Fox News. 

The pre-teen died Sunday at a Milwaukee hospital and the cause of death is listed as multiple blunt force injuries to the head.

Andrez Martina, left, and his grandson, Andre Smith II.  (Milwaukee Police/Family Handout)

Martina told police he awoke about 3 a.m. Sunday to find his wallet open and money missing. The victim, who was sleeping over at Martina's house along with an 8-year-boy, denied taking the money and turned his pockets inside out to show they were empty, according to the complaint.

The complaint said that after he beat the boy, Martina took the child into the shower and attempted to rinse off his blood. The victim was not taken to the hospital until about 9 a.m. About 45 minutes after arrival, doctors pronounced the boy dead, FOX 6 reported

Investigators interviewed Martina Monday. He told them he returned to Milwaukee from Indiana earlier this year because he "wanted to reconnect with his grandchildren." 

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According to the criminal complaint, Martina learned that Smith "had a problem stealing" and he recalled telling his grandchildren previously, "if you lie, if you mess up in school, if you steal, I’m going to kill you." 

During the interview, Martina also admitted to killing a boy in 1989, according to the complaint. A search of his residence allegedly turned up drugs and firearms. 

Martina is facing a litany of charges including first-degree intentional homicide, physical abuse of a child with repeated acts causing death, and neglecting a child, among others. He is also accused of striking the 8-year-old, breaking his finger and bruising his body.

If convicted, he could face up to two life sentences, plus 60 years in prison and a possible fine of $225,000, police said. 

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Court documents do not list an attorney for Martina who could speak on his behalf. 

The Associated Press contributed to this report