Four men from the Liverpool area have been arrested on suspicion of assisting an offender in connection with the escape from custody of murderer Shaun Walmsley in the city on 21 February.
The men, two aged 24 and two aged 25, were in a Vauxhall Corsa stopped in a vehicle by armed Dorset police who shot tyre deflation rounds in Haven Road, Canford Cliffs on Friday afternoon (3 March) and are being questioned in Merseyside.
Walmsley was not among those detained.
In a statement, DCI Gavin Dudfield, of Dorset police, said: "Dorset police responded to reports that a number of people involved in the unlawful escape of Shaun Walmsley were travelling through Dorset. This was a successful, targeted operation and I would like to thank all the officers involved, including our alliance colleagues at Devon and Cornwall police as well as Merseyside police.
"I appreciate that due to the nature of the incident there may have been some concerns in the local community, so I would like to thank the public for their patience and understanding while these necessary arrests were made."
Walsmley was serving a life sentence with a minimum 30 year term at HMP Walton for the "vicious and savage" stabbing of Anthony Duffy in Liverpool in 2014. Duffy had been lured to an address in Anfield where he was ambushed by Walmsley and three other men.
Walmsley was visiting Aintree University Hospital in Merseyside when officers escorting him were confronted by two men armed with a gun and knives. The three men fled in a Volvo, later found abandoned.
Two men and a woman were arrested in connection with the escape in Liverpool on 24 February. They were later released pending further inquiries.