The Bloody Sunday families have met with the PSNI to discuss how the investigation, which resumed earlier this month, is progressing.
They spoke to Detective Chief Inspector Ian Harrison and his team at Maydown on Friday about the resources being made available for the police inquiry.
Speaking afterwards, solicitor Peter Madden said it had been a “very positive” meeting.
“The detective chief inspector has confirmed that this is a murder investigation and that it is back to the same level of resources it had before it was scaled down,” he told UTV.
Thirteen people were shot dead in the Bogside area of Londonderry on 30 January 1972 after British paratroopers opened fire on crowds at a civil rights demonstration.
Fourteen others were wounded and one later died.
A PSNI probe had been launched following the publication of the Saville Inquiry in 2010 which found that those shot and wounded were innocent.
However the investigation was effectively brought to an end last year due to financial constraints.
Then in January, police said the investigation would resume and would form part of the work of the Legacy Investigation Branch.
Following Friday’s meeting Mr Madden said that police had not indicated when they plan to start interviewing military witnesses.
He continued: “The detective chief inspector said he is not going to reveal his tactics but that will come eventually, it will come in due course.”
