One of the Boston bombing suspects is dead and the second is on the loose and said to be ‘armed and dangerous’ after a dramatic shootout in the suburbs of the city.

The terrorist dubbed ‘Suspect 1’ by the FBI died in hospital with multiple gunshot wounds and possible blast injuries after a fierce gun battle rocked the Watertown area hours after a police officer was shot dead at the nearby MIT campus.

The other, named today as 19-year-old Dzhokhar A. Tsarnaev, of Cambridge, Massachusetts, who was seen on CCTV wearing a white baseball cap, has gone on the run.

Boston Police Chief Ed Davis said: ‘There is a terrorist on the loose who wants to kill people – do not open your door’.

Today, sources said the suspects were believed to be brothers from the Russia region near Chechnya and had lived in U.S. for at least one year.

Boston was in lockdown as police hunted the second suspect through the streets, with all mass transit shut and residents warned to stay inside.

A transit police officer was critically wounded in the exchange of gunfire with the suspects, police added.

Dzhokhar A Tsarnaev is believed to be a legal immigrant to the U.S., who arrived in the country one year ago from Chechnya.

He may have had military training, according to NBC. The 19-year-old, who attended Cambridge Rindge and Latin School, is an amateur wrestling champion.

‘Suspect 1’ who died in hospital is believed to be 20 years old and the brother of ‘Suspect 2’ Dzhokhar.

The older brother attended Bunkerhill Community College and was studying to become an engineer but took a year off to pursue boxing.

The drama unfolded hours after the FBI released images of two men named as suspects in the Boston blast which killed three and injured 176 on Monday.

The Middlesex district attorney said the two men are suspected of killing a Massachusetts Institute of Technology police officer on campus in Cambridge late last night, then stealing a car at gunpoint.

Dozens of police officers, FBI agents, national guard, K-9 units and SWAT teams rushed to Watertown after midnight after a reported car chase involving the two suspects in a black 2013 Mercedes.

A short time later, police received reports of a carjacking by two men who kept their victim inside the car for about half an hour, the statement said.

Police pursued that car to Watertown, where explosives were thrown from the car at police and gunfire was exchanged, the statement said.

‘During the exchange of the gunfire, we believe that one of the suspects was struck and ultimately taken into custody.’

A doctor from Beth Israel Deaconess Medical Center said the suspect died after suffering multiple wounds from gunshots and possibly the blast of an explosive.

Read more: UK Daily Mail