An image of one of the suspects was obtained after a high-powered motorcycle, believed to have been used as a getaway vehicle, was found abandoned near a lake in Danau Kota, Kuala Lumpur, about 2km from the scene of shooting.
Fadi al-Batsh in Malaysia on Saturday, alleging that Israeli agents were systematically assassinating Arab scientists.
The men were believed to have entered Malaysia in January but their nationalities were still not known, police said.
Tan Sri Fuzi said: "It's not going to be easy to track them down as we believe they're using a fake identity".
Al-Batash's body was expected to return to Gaza at 2:00 p.m. local time accompanied by his wife and two sons, who also reside in Malaysia.
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The pictures show two light-skinned, bearded men, one of whom was wearing glasses and a white and black helmet.
Since March 30, Palestinians have been staging rallies along Gaza border demanding the return of refugees to their towns and villages in historical Palestine from which they were driven in 1948 to make way for the new state of Israel.
Based on eyewitness description, Malaysian police earlier released computer-generated images of the two suspects, believed to be from Europe or the Middle East.
Israeli soldiers arrested two Palestinian men who crossed into Israel from Gaza armed with a grenade and a knife.
The Gaza health ministry announced he had died after receiving treatment inside Israel, which the Sheba hospital near Tel Aviv confirmed.
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Batsh's expertise in making weapons could have made him a target - militants in Hamas-ruled Gaza regularly fire rockets at southern Israel, usually without causing casualties.
Israel claimed he was a Hamas member, but provided no evidence.
Israel has a long history of being accused of targeting wanted Palestinian militants in daring overseas operations and has been linked to other assassinations as well, though it has rarely publicly acknowledged them.
Israel's Defense Minister Avigdor Lieberman had appealed to Egypt to refuse the Palestinian request.
Batsh was a lecturer at Universiti Kuala Lumpur, specializing in power engineering, according to the university.
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