(CNN)Three pink ceramic kitchen knives found on or near the assailants who killed seven people in the London Bridge terror attacks have investigators seeking the public’s help for clues.
Commander Dean Haydon, head of the Metropolitan Police’s counterterrorism unit, said early Saturday that authorities want to know more about the unusual knives.
“Where have they come from? Where might the attackers have bought them from?” he asked through a news release that included photos of one of the knives used by the terrorists.
The knives are 12 inches long and are branded Ernesto. Tape was wrapped around the handles.
Police said three men — Khuram Shazad Butt, 27; Rachid Redouane, 30; and Youssef Zaghba, 22 — rammed a van into pedestrians on London Bridge last weekend before launching a stabbing spree in bars and restaurants at nearby Borough Market. Police shot the attackers dead.
Police also released photos of the van the attackers used to mow down people on the bridge.
Inside, they found 13 apparent Molotov cocktails made from wine bottles and a possible flammable liquid. There also were two blowtorches.
Haydon appealed for more witnesses to come forward.
“My officers are particularly keen to hear from anyone who witnessed the white van targeting individuals on London Bridge, saw the suspects attacking members of the public or saw armed police engaging the suspects,” he said.
Investigators have spoken with 262 people. People can call 0800 789 321 with information or fill out a form at gov.uk/ACT.
Police have arrested 20 people in connection with the attack, seven of whom are still in custody. That includes a 27-year-old man arrested in the Ilford district in east London and a 28-year-old man arrested in the London suburb of Barking.