In just one day, Isa Ahmad, 52, allegedly robbed one woman and attempted to rape another. Both incidents took place in the Orchard area.
Yesterday, a court heard that Isa is also believed to be involved in other cases, but no details were revealed.
Isa, who is being remanded at the Central Police Division, was charged with robbery and attempted aggravated rape.
He is accused of attempting to rape a 27-year-old woman in a room at the Hilton Hotel in Orchard Road between 11.29am and 11.33am on Sunday.
About six hours later, he allegedly went into a lift at the nearby Tang Plaza and robbed another woman, Ms Wai Wai, 48, taking an Apple iPhone 6. Court documents did not mention how much the device cost.
In a release on Tuesday evening, police said that they were alerted to the attempted rape around 12.50pm on Sunday. According to the police, the assailant fled the room after the woman put up a struggle.
While the investigation into the attempted rape was still ongoing, officers received a report about the robbery at around 6pm.
Officers from Tanglin Police Division, the Criminal Investigation Department and the Police Intelligence Department tracked Isa down and arrested him within 24 hours of the first report.
Isa, who was unrepresented, will be back in court on Wednesday.
If convicted of attempted aggravated rape, he could be jailed for up to 20 years.
And if convicted of robbery, he could be jailed for between five and 20 years.
He cannot be caned as he is above 50 years old.