Aug. 25 (UPI) — British authorities said a dozen people have been arrested in an investigation following a weekend crash that killed seven people, including two police officers.

Police in Cleveland, which serves the Teesside area of northeast England, announced the arrests Monday, identifying those detained as nine men and three women between the ages of 19 and 61.

They were detained on a range of offenses, including allegations of participating in organized crime, possession of an offensive weapon and drug-related crimes.

The suspects were detained over the weekend in a wide-scale investigation following a collision early Saturday involving a Volkswagen Passat and a police vehicle on the A66, resulting in the deaths of the five occupants of the Passat and two officers in the police vehicle.

Authorities were initially alerted early Saturday to reports of two vehicles being driven dangerously in Middlesbrough. A Volvo XC60 was reportedly seen ramming properties, while a Volkswagen Passat was believed to be associated with the Volvo. Police said both vehicles were operating with cloned license plates.

Police later spotted the Passat and pursued it for nearly seven minutes before the Passat entered the A66 at South Bank, traveling against traffic, prompting the pursuing police vehicle to end its case.

However, seconds later, at 3:39 a.m. local time, the Passat collided with a second police car, which was traveling in the correct direction, authorities said.

The deceased officers have been identified as Matthew Blades, 37, and Tom Clough, 38. The deceased occupants of the Passat were named as Cole Robert Worthy, 17, Theo Rae, 17, Makai Saddington, 18, and 23-year-olds Jakub Matusiak and Michael Robert Cahill.

“The events of that tragic night will have a lasting and profound impact on the Cleveland area and the communities we seek to protect,” Assistant Chief Constable Wayne Fox said Monday in a statement.

Fox said they have a duty to investigate the “serious criminal activity” that led to the fatal crash and bring those responsible to justice, though it was not clear how those detained were involved.

“Our robust response will continue in the weeks and months to come, as we continue to tackle those that seek to cause harm to our communities and tackle serious and organized crime,” Fox said.