After strong criticism from a federal lawmaker, the online betting platform Polymarket stopped accepting wagers on when US warplane crew members who were shot down in Iran might be rescued. It promised to investigate how the market materialized.

The criticism came from Seth Moulton, a Massachusetts Democratic representative who earned two bronze star medals serving with the United States marine corps in Iraq from 2003 to 2008 and published an X post describing Polymarket’s acceptance of bets on the downed pilots’ fate as “DISGUSTING”.

Prior to Moulton’s post, Iranian military forces on Friday had shot down an F-15E Strike Eagle jet occupied by two US air force members participating in the war on Iran being waged by the US and Israel since late February.

The aircraft’s pilot was rescued within seven hours. Donald Trump announced the other crew member’s rescue just after midnight Sunday through a post on his Truth Social platform.

For a time, Polymarket permitted users to wager on the timing of those rescues, with most betting they would occur by Saturday.

Moulton did not take kindly to learning that the platform was allowing such bets. While the search and rescue efforts for the downed jet crew were in full effect, Moulton wrote on X: “Their safety is unknown… And people are betting on whether or not they’ll be saved. This is DISGUSTING.”

Polymarket’s X account replied to Moulton: “We took this market down immediately as it does not meet our integrity standards. It should not have been posted, and we are investigating how this slipped through our internal safeguards.”

Moulton countered in another post that Polymarket was still accepting hundreds of other war-related wagers that it should deactivate, adding that the company’s “integrity standards are severely lacking”. At one point during the exchange, Moulton mentioned that the president’s oldest son and namesake, Donald Trump Jr, is an investor in Polymarket, which the congressman referred to as a “dystopian death market”.

“Taking down this particular bet after I called it out can only be the first step,” Moulton wrote.

Polymarket did not immediately respond to a request for additional comment on Moulton’s condemnation or details about the investigation it vowed to undertake.

The company’s dialogue with Moulton came after some Polymarket users in March generated international news headlines by sending threatening messages to an Israeli journalist after some of his reporting on a missile strike near Jerusalem became the focus of an unresolved bet related to the war in Iran.

Platforms such as Polymarket, where users can bet on matters ranging from war and elections to entertainment industry awards and sports, have drawn congressional scrutiny as they accumulate an exponentially growing number of betters.

Congressional lawmakers in March introduced a proposal to ban prediction markets from accepting bets pertaining to sports or casino-style games. And a separate but similar proposal in March called on banning prediction markets on government actions, war and “events ripe for rigging”.

In a statement about the latter of those two measures, Chris Murphy, a Democratic US senator of Connecticut, said: “When events that involve good and evil, life and death become just another financial product, morality no longer matters and the soul of America is fundamentally corrupted.”