This criminal suspect’s apparent love of tattoos may be his downfall.

Police in Germany who found the body of a 20-year-old woman stuffed inside plastic garbage bags late last month knew someone had cut her throat, but they were unable to determine when the crime occurred. They now believe the prime suspect has unwittingly solved the mystery.

The suspect, identified by Newser as the victim’s 27-year-old boyfriend, Dominik Riedl, was taken into custody Sunday, after German authorities used bank records to trace him to Spain. Riedl reportedly had the couple’s 18-month-old toddler with him when he was arrested. He sported several tattoos, including suspicious fresh ink on his upper left arm, authorities said.

According to Spanish police, the new tattoo included a cross with the name of Riedl’s deceased girlfriend, the date of her birth and an ominous date.

“This most recent and macabre one with the October 27th date on it can be interpreted as the date of her death,” Spanish National Police said in statement.

Policia Nacional Another photo of the suspect that was released by police

Riedl’s new tattoo includes an inscription in Spanish that translates to, “Thank you for everything.”

Authorities said the tattoo is a vital piece of evidence they will use to connect Riedl to the slaying of his girlfriend, who they didn’t name.

Riedl is suspected of using her cellphone, after her death, to update her social media accounts. It was an apparent attempt to throw off investigators, police said.

Riedl is being held on a fugitive warrant in Spain, pending extradition to Germany. His son has been placed with social services.