Malki was reportedly gunned down by three gunmen who opened fire on his car in the western Turkish city.
His killing was the second attack on Jews in recent months.
In June, a militant Islamic group claimed responsibility for a car bomb attack that injured the leader of the Jewish community in the capital of Ankara.
Malki's murder prompted the ADL to write a letter to Turkey's ambassador to the United States, Nuzhet Kandemir, calling on Turkey to investigate the attack and to beef up security for the country's Jewish community.
"The Anti-Defamation League has grown increasingly concerned by anti-Jewish violent attacks within Turkey," wrote ADL national director Abraham Foxman.
"The government of Turkey must step up its efforts to protect the Jewish community of Turkey and do all it can to prevent future terrorist attacks."
There are an estimated 25,000 Jews living in Turkey, a secular state whose population is predominantly Muslim.