A US district judge has ordered a new delay in federal executions, hours before the first in 17 years was due to go ahead.
He was convicted in Arkansas of the 1996 killings of gun dealer William Mueller, his wife, Nancy, and her eight-year-old daughter, Sarah Powell.
Now US District Judge Tanya Chutkan said there are still legal issues to resolve and that “the public is not served by short-circuiting legitimate judicial process”.
The execution, pushed by the Trump administration, would be the first carried out at the federal level since 2003, following a de facto moratorium under Barack Obama.
The execution had previously been delayed after the victim's family argued that they would have to take part in high risk travel to attend during the pandemic. But a federal appeals court lifted the injunction on Sunday.
The family had vowed to appeal to the Supreme Court.
The Trump administration is likely to ask a higher court to allow the executions to press ahead with the executions.
While Texas, Missouri and other states execute multiple inmates each year, federal executions are rare.
Only three have occurred since 1963, all between 2001 and 2003, including the 2001 execution of the Oklahoma City bomber Timothy McVeigh. Some 62 people are currently on federal death row in Terre Haute.
The decision to move forward with Lee’s execution – and two others scheduled later in the week – during a global health pandemic which has ravaged the country’s prisons has drawn criticism from civil rights groups.
Critics have argued that Mr Trump is creating an unnecessary and manufactured urgency around a topic that is not high on the current list of American concerns.
Five US states broke records for average daily fatalities last week, and a new daily record of 66,528 coronavirus cases were recorded in the US on Saturday.
At least 3,290,000 cases and more than 132,000 deaths have been reported in the country.