Police are asking for help from the public after three incidents in the Bourne and Market Deeping areas over the weekend.
Three men in a black Volkswagen Passat were seen acting suspiciously near farm buildings on South Fen Road, Bourne. at about 11.30am on Sunday.
The car sped off when they were seen and farmers are being advised to look out for the vehicle in the area.
Meanwhile in Aslackby, two men thought to be in their early 20s and driving a small blue van were seen in a garden and when approached someonne living there, claimed to be water board workers.
It happened at about 10.30am on Saturday and one of the men is described as being 5ft 10in tall and having a goatee beard.
The van is thought to have a registration number similar to RX10ZW.
Finally, a youth threw an object at a car window in Godsey Lane, Market Deeping, at about 6.30pm on Friday.
Police are trying to trace two people aged 17 to 18, one of whom was wearing a black baseball cap and the other had on burgundy jeans.
Anyone with information should call 101, quoting incident number 212 of July 28 (Bourne), 202 of July 27 (Aslackby) or 450 of July 26 (Market Deeping) incidents.