A fourth police officer who defended the US Capitol during the 6 January insurrection by extremist supporters of Donald Trump is now confirmed to have taken his own life.

Washington DC’s Metropolitan police department (MPD) confirmed late Monday that another of their officers, Kyle DeFreytag, died by suicide earlier in July, just hours after declaring that MPD officer Gunther Hashida killed himself on 29 July.

In January MPD officer Jeffrey Smith, a 12-year veteran of the force, and Capitol police officer Howard Liebengood, a 16-year veteran, both of whom also responded to the 6 January attack, died by suicide.

DeFreytag, who was 26, was deployed to protect the Capitol after police cleared the building of rioters, and was involved in enforcing a curfew, the department said.

The MPD chief, Robert Contee, had notified personnel of DeFreytag’s death on 10 July in a department-wide message, the department confirmed.

He had been an MPD officer for five years, according to his obituary.

Hashida had helped secure the Capitol on 6 January as part of the emergency response team within MPD’s special operations division after a mob of thousands of Trump supporters stormed the building.

The announcement of the deaths of DeFreytag and Hashida came a week after several officers testified to a House of Representatives select committee investigating the 6 January insurrection, when extremists stormed the Capitol to try to stop the certification of Joe Biden’s win over Trump in the 2020 presidential election.

That attempt failed and Biden’s victory was successfully certified by Congress in the early hours of the following morning.

But the attack on the Capitol, which lasted several hours, involved rioters assaulting outnumbered officers to break into the building in a failed effort to hunt down lawmakers, including the then vice president, Mike Pence.

Trump was impeached, for an unprecedented second time, on the charge of inciting the insurrection, and acquitted in February by the Senate.

Almost 600 people have been criminally charged for their part in the events.

• In the US, the National Suicide Prevention Lifeline is at 800-273-8255 and online chat is also available. You can also text HOME to 741741 to connect with a crisis text line counselor. In the UK and Ireland, Samaritans can be contacted on 116 123 or email jo@samaritans.org or jo@samaritans.ie. In Australia, the crisis support service Lifeline is 13 11 14. Other international helplines can be found at www.befrienders.org