LONDON (AP) — British police have described the painstaking work of recovering remains from a burnt-out London high-rise, four weeks after the disaster killed at least 80 people.

The Metropolitan Police force says it will take months to identify all the victims, and the agonizing wait has provoked anger and dismay from victims' families.

Police say they believe 80 people died in the June 14 fire. So far, 32 victims have been formally identified.

Sgt. Alistair Hutchins, part of the force's victim identification unit, says officers are carrying out a methodical search of devastated Grenfell Tower, using shovels and sieves to retrieve fragments of bone and teeth.

In an interview released Wednesday by police, Hutchins said he understood the frustration of victims' families, but promised "we are doing our utmost best for you."