Nearly 70 residents sickened with the coronavirus have died at a Massachusetts home for ageing veterans, as state and federal officials try to figure out what went wrong in the deadliest known outbreak at a long-term care facility in the US.

While the death toll at the state-run Holyoke Soldiers’ Home continues to climb, federal officials are investigating whether residents were denied proper medical care and the state’s top prosecutor is deciding whether to bring legal action.

“It’s horrific,” said Edward Lapointe, whose father-in-law lives at the home and had…