KUALA LUMPUR, Malaysia—Investigators hunting two men accused of shooting and killing a Palestinian electrical engineer in the street described them Monday as Middle Eastern or European in appearance and said they may have fled this Southeast Asian country.

Police appealed to the public for help in locating the men, who have left the Malaysian government struggling with a second high-profile assassination little more than a year after the estranged half-brother of North Korean dictator Kim Jong Un was killed in Kuala Lumpur’s international airport.

The slaying of Fadi al-Batsh by two men on a motorcycle as he walked from his home to a neighborhood mosque for dawn prayers Saturday has been blamed by his family and the Hamas organization, which runs Gaza, on the Israeli secret service, Mossad. Israel has rejected responsibility and says he may have died in a score-settling between terror groups.

The pair of killings highlight a vulnerability for Malaysia, a moderate Muslim country of some 30 million people that is to hold closely contested elections May 9. Government officials have made few comments about the killing and the alleged vulnerability of security policy and didn’t respond to fresh requests for comment Monday.

Wong Chen, an opposition politician, said that the administration of Prime Minister Najib Razak should have cut off diplomatic ties with North Korea last year.