They disappeared as mysteriously as they appeared, but the brutality they unleashed in Belgium in the 1980’s still haunts and baffles.

The latest twist in the cold case murders carried out by a gang known as the “Crazy Brabant Killers” is the arrest of a former police officer who investigated the case and now is suspected of hiding evidence.

The gang killed 28 people in Belgium, sparing no one in their path – not even children. They hid their identities with face paint, earning titles such as “the Giant,” “the Killer,” and “the Old Man,” who was the getaway driver, according to The Guardian.

On Wednesday, authorities arrested the police officer, identified in the newspaper only as Philippe V. The officer was expected to appear in court on Thursday.

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The newspaper says authorities were looking into a link between Philippe V. and evidence from the gang’s crimes that were found in 1986 in a canal. Investigators, the newspaper said, had not come across the evidence – which included a bulletproof vest, and police officer’s stolen gun – when they searched the canal the year before.

Eric Van Der Sypt of the federal prosecutor’s office raised the possibility the evidence was tossed into the canal shortly before police looked a second time.

"It is clear that when you dive in 1985, you cannot find anything,” Van Der Sypt said, according to The Guardian. “When we dive again in 1986, we find a lot of objects, which is not normal.”

The Guardian quoted another, unnamed, source from the prosecutor’s office as saying that they interrogated Philippe V. about whether he had “retained at least certain, possibly crucial, information.”

The Crazy Brabant Killers went on their rampage for three years, hitting supermarkets, bars and hostels, among other places. They actually took very little, but their crimes often ended in bloodshed. They shot everyone, including children, and seemed to relish taunting their victims by shouting at them.

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Their spree stopped in 1985, and their identities remained a mystery. Their final bloody attack was in a supermarket, where they killed eight people using pump-action shotguns. The dead included a 9-year-old girl who was sitting in a car outside the supermarket.

The gang's disappearance didn’t stop wild speculation, including that the killers, who seemed to have firearm expertise, were part of a former paramilitary force.

Walter Damen, Philippe V.’s lawyer, said the former police officer denies he did anything wrong, The Guardian reported.

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“He says that he did not influence the investigation at all, that he had no contact with the band of Brabant killers … In January 2019, he is asked for information on November and December 1986. It is difficult, because [to] each sentence must be added ‘I think’ or ‘I do not know,’” Damen said.