Police believe the same well-dressed man is behind two bungled bank holdups in 48 hours in which bomb threats were made to staff.
The middle-aged robber, who wore dark-framed glasses, a tie, a black jacket and leather shoes, fled empty-handed on both occasions as bank employees ignored his demands and threats and pressed panic buttons.
Last night, police were still looking for the man, aged about 40, slim and 1.7 metres tall.
The latest failed holdup happened in Sham Shui Po yesterday, when the man, carrying a backpack, went into the China Citic Bank branch on Yu Chau Street shortly after 2.30pm.
He gave a female teller a note claiming he had a bomb and demanding HK$10,000.
"The robber fled empty-handed as the teller activated the alarm," Chief Inspector Wallace Lee Che-hung of Sham Shui Po district crime squad said.
The robber ran out of the bank and fled on foot.
A team of police officers investigating a nearby mugging raced about 200 metres to the bank and searched for the man but could not find him.
Police suspect the man also tried to rob a Wing Lung Bank branch in Sau Mau Ping at about 3.15pm on Tuesday. He fled empty-handed when a female employee ignored his threat and demand for HK$100,000 and pressed a panic button.
The chief inspector believes the two cases were carried out by the same man because the descriptions were similar.
In a separate investigation, police are looking for a mugger who attacked a 76-year-old man on Yu Chau Street, slashing him and escaping with his bag and mobile phone.
The attack took place at about 7pm on Wednesday.
Last night, the victim, who suffered more than 10 cut wounds to his neck, head, chest and hands, was in critical condition in Queen Elizabeth Hospital in Yau Ma Tei.
Police received four reports of bank robberies last year and three in 2012.
Reports of all types of robbery fell to 500 last year from 616 in 2012; 713 in 2011; and 778 in 2010. In 2002, there were some 3,493 robberies.