Lincolnshire Police arrested two men on suspicion of stealing bicycles in Lincoln on Thursday.
Officers stopped a 20-year-old and a 33-year-old man on the High Street at around 3am on February 9, and two bikes were seized, alongside a quantity of drugs.
The suspects are currently helping with enquiries at Lincoln Police station.
The arrests are after repeated warnings to the public to make sure their bicycles are locked up safely.
Warnings come after a 50% increase in bike thefts in the city from the last year, particularly in the city centre.
Police advise expensive bikes should be kept indoors, or in a secure shed, and residents should buy a strong lock when leaving the bike in a public place.
Insp Mark Garthwaite said: “We’re seeing an increasing number of reports of bicycles being stolen. They range in value and type from cheap ladies shopping bikes to high-end mountain bikes worth thousands of pounds.
“Please try to use the best lock you can afford, ideally a sturdy D-lock and attach them to something fixed that is visible to passers-by – ideally under CCTV cameras.
“There are also a number of security marking kits available quite cheaply that make bikes less attractive to a potential thieves.”
Anyone with information on bike thefts should call Lincolnshire Police on 101 or Crimestoppers on 0800 555 111.