( CNN ) -- Bulgarian police have widened their investigation into last week 's bombing attack on Israeli tourists to towns near the border with Romania , asking hotels for surveillance video that might have captured the suspected bomber . Hotels in the Black Sea coastal city of Varna say police have been asking for video showing a particular suspect and are giving a sketch of the suspect to management . Investigators also have questioned workers at a car rental agency near the Black Sea coast where the man attempted to rent a car before Wednesday 's attack , the agency 's owner told CNN . Five Israeli tourists were killed and more than 30 other Israelis were wounded when a suicide bomber blew apart their bus at Burgas International Airport . Explainer : Bulgaria explosion amid growing Iranian-Israeli tension . Bulgarian authorities still have not been able to identify the bomber , who was seen on airport security videos about an hour before the attack . They have taken fingerprints and DNA samples and given that information to their counterparts in Israel , the United States and Interpol . The Bulgarian Interior Ministry says it is not ruling out the possibility that the suspect had help , though it wo n't comment on reports that authorities are looking for a second suspect . The owner and an employee of the Afrodita Car Rental Agency told CNN a suspicious man wanted to rent a car the Sunday before the attack and tried to use the Michigan driver 's license later found at the scene of the attack . When the owner said he wanted to photocopy the license , the man grew nervous and refused to have it copied . At that point , the owner said he refused to rent the man a car and the man walked out . The car rental owner described the man as having short dark hair and speaking English with an accent . The woman who conducted the forensic reconstruction of the suspected bomber 's face and body , told Bulgarian TV the man had a white face , light eyes and thick dark hair .
Police are checking hotels for surveillance video . The suspect was also seen at a car rental agency . Two Israelis were killed in a suicide bombing last week . Police do n't rule out the possibility of a second attack .