The murderous trio behind the London Bridge attack filled their van with petroleum bombs, used mysterious ceramic pink knives and originally planned to rent a 7.5-ton truck, suggesting that they intended more carnage before officers shot them dead, police said Friday.

Metropolitan Police in London appealed for information about the ceramic knives used in last weekend’s attacks that killed eight people. The non-metallic nature of the knives suggests the killers may have been concerned about metal detectors.

“We’ve been working round the clock to understand what these men did in the lead-up to the attack but we need to know more about these unusual knives,” said Commander Dean Haydon, head of the Metro Police Counter Terrorism Command.

“Where have they come from? Where might the attackers have bought them from?” Haydon said in a statement. “If you know anything about these particular types of knives, please let us know — it could prove a crucial lead in our investigation.”

The kitchen knives, each measuring about 12 inches, are branded Ernesto, police said. The attackers had wound duct tape around the handles and, in the case of attacker Khuram Shazad Butt, a leather strap had been attached to the handle and was hung around his wrist.

An Internet search reveals that a German-language shopping site sells what appears to be the knives, or at least something that is extremely similar.

In a rare glimpse into the weeklong investigation, police released details on Saturday that showed Butt originally tried to rent a 7.5-ton truck. The intended truck was smaller but similar to the one used in the Nice attack last year that killed 86 people and injured hundreds in the resort town in the south of France.

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SOURCE: USA Today, Mike James