Detective Derek Williamson said that CCTV captured "some of the events here".
CCTV footage may hold vital clues for detectives hunting the killers of two young soldiers at their base in Antrim.
Sappers Mark Quinsey, 23, from Birmingham and Patrick Azimkar, 21, from London, were shot dead by the Real IRA at Massereene Army base.
Detective Chief Superintendent Derek Williamson said "some of the events" from the attack on Saturday night had been caught on camera.
He said a car found about seven miles from the base was the getaway vehicle.
The green Vauxhall Cavalier TDZ 7309 was found in Randalstown and had been bought two weeks ago, said Det Ch Supt Williamson.
The Army's bomb experts are examining the car as a precautionary measure and it will then be examined for clues by forensic officers.
"We have some information about its history, but we need to find out more about its movements on Saturday night and in the past two weeks," Det Ch Supt Williamson told a news conference.
"We need to know where it's been, who was in it, and where they are now.
"This is an important line of enquiry and we need people to come forward."
Northern Ireland Secretary Shaun Woodward said the attack was a "sickening crime" and a "premeditated attempt at mass murder," involving more than 60 shots.
"This has been a very dark few days for Northern Ireland," he told the House of Commons.
"But it is a temporary darkness at the end of a tunnel of considerable light."
Tributes have been paid to the two soldiers.
The Army commander in Northern Ireland said the two men had been "magnificent individuals".
Brigadier George Norton said the men had been killed in a "callous and clinical" attack.
Prime Minister Gordon Brown visited the base and met NI political leaders on Monday. He said the peace process was "unshakeable".
"What I've seen this morning is the unity of the people of Northern Ireland, and the unity of the political parties," he said.
"That they are going to continue to work together and they want to send out a message to the world - as I do - that the political process will not and never be shaken.
"In fact, the political process is now unshakeable."
Four other people, including two pizza delivery men - Anthony Watson, 19, from Antrim and a Polish man in his 30s - were injured in Saturday's attack.
Prime Minister Gordon Brown said the NI political process is 'unshakeable'
One of the delivery men is in a serious condition in hospital. It is understood the others are in a stable condition.
The rest of 38 Engineer Regiment has now left the base and gone to Afghanistan.
"They will not allow the actions of a few loathsome individuals to distract them from the job in hand," Brigadier Norton said.
The Army commander was asked why no fire had been returned from the base during the attack.
"Are you suggesting that people should have fired into a closely packed group including my five soldiers," he said.
"Both the guard service and the soldiers did everything that they could possibly do to save the lives of those who had been shot, including obviously the pizza delivery individuals, and I'm delighted by the way they responded but in no way surprised."
Secretary of State Shaun Woodward is due to make a statement about the murders in Parliament later.
The two young soldiers were the first to be murdered in Northern Ireland in 12 years. Lance Bombardier Stephen Restorick was killed by an IRA sniper in 1997.
Sinn Fein president Gerry Adams said the murders were "an attack on the peace process".
"It was wrong. It was counter-productive.
"My thoughts are with the families of the two men who were killed and who were injured," he said.
"And you might take some succour from the fact that whoever was involved, they have no support and no strategy and no popular will to back up their actions."
The attack has forced a review of security at police and military bases in Northern Ireland.
Northern Ireland's First Minister and Democratic Unionist Party leader Peter Robinson offered his sympathies to the families of the victims.
Speaking to the Assembly on Monday, he said it was "a futile act and a terrible waste".
"The events of Saturday evening were a throwback to a previous era. We must never return to such terrible days," he said.
"The police need the support and cooperation of the entire community.
"Let the answer be loud and clear: We are not turning back."
HOW THE ATTACKS UNFOLDED
SATURDAY 7 MARCH: 1. Soldiers order pizza from delivery shop in Antrim. Two cars leave shop at about 2120 GMT 2. Four soldiers collect pizza from main gate at Massereene Barracks. As they do, two gunmen open fire from a nearby car. Two soldiers - Mark Quinsey, 23, and Patrick Azimka, 21 - are killed, four people seriously injured including the pizza delivery men 3. Vauxhall Cavalier which police believe the gunmen to have used recovered in Ranaghan Road, nr Randalstown
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