Frustrated police officers are being forced to give stolen goods back to suspected thieves because they can't prove they have been taken.
Officers admit they are having to hand back likely loot because they can not trace the genuine owners.
Even expensive items, including bikes worth thousands of pounds, are being given back to suspected criminals.
It happens because the law bans police from keeping it without clear proof that a theft has taken place.
Officers say the situation is not new, but that most people will not be aware it happens.
Now, in a drive to urge people to protect their possessions, it is hoped the news will shock more people in to marking up their property.
The head of community safety at Lincolnshire Police, inspector Phil Baker, said: "We will seize items if we suspect them to be stolen. What we then do is try to search to see if they have been reported stolen and if not, we then have to make a decision on whether we give them back. If you can't prove who the bike belongs to, it can go back to the thief.
"I had it with two bikes in the Gainsborough area and I tried to fight tooth and nail to prevent them going back to potential offenders.
"They were worth £2,000 to £3,000 each so were seriously expensive. I even went to a British cycling organisation to try to track the owners.
"It's not what we are out there for. We always urge members of the public to lock their bikes up and secure it with a D-Lock.
"It's not what we want to do but we do on occasion have to return it to those we have taken it from.
"We can try to use the Police Property Act to see if we can retain it but it's very difficult because we need to demonstrate that they do not have a legal right to the property.
"You can literally go into the basement of the police station and there are hundreds of bikes for which we don't have any owners or they are not registered and we'll never be able to trace them.
"From April to December last year, there were 1,800 bikes stolen across the county.
Inspector Pat Coates, who is responsible for Abbey ward, said: "In the south of the city, we recovered a number of mountain bikes and we had to give them back, which it galls us to do.
"It doesn't always happen but sometimes we have no choice. Of course, the poor victim is still missing their property."
Ann Walton, 68, of St Botolph's Crescent, off High Street, Lincoln, said: "Everything seems to be on the criminal's side.
"There seems to be an attitude that 'I won't be burgled' but why should we let the criminals win?
"It's quite simple to get your bike, gardening tools or even your telly postcode stamped."
Sophie Barker, 38, of Boultham Park Road, Lincoln, said: "I can understand where the police are coming from but in this country you're innocent before being proved guilty.
"It's a difficult one. It seems unfair that suspected criminals appear to benefit but I think the police have their hands tied on this one."
Despite the news, burglaries across the county have dropped by 12 per cent since last year, thanks to policing initiatives and communities.
Force-wide, between April 2010 and January 2011 there were 2,063 house burglaries. From April 2011 and January 2012 there were 1,817.