Police investigating a series of suspected "crash-for-cash" insurance scams have carried out a number of raids.
Officers from Thames Valley Police executed five synchronised warrants in Reading, Berkshire, at 7am today as part of Operation Shunt.
It is an investigation into so-called "crash-for-cash" cons where crooks deliberately cause road crashes in order to commit insurance fraud.
Police said the warrants related to six complaints in the South and Vale, Abingdon and Oxford areas between March and September last year.
Detective Inspector Louise Roddy, from Thames Valley Police, said: "These crash-for-cash schemes involve serious fraud.
"We are working to bring the offenders to justice because not only does their crime put insurance costs up, it also puts members of the public at risk of being involved in one of these induced collisions."
Police said three men, aged 39, 38 and 30, all from Reading, were arrested on suspicion of fraud.
A fourth person, a 27-year-old man, was held by immigration enforcement officers pending removal from the UK.
In addition, a substantial sum of cash was seized from one of the properties under the Proceeds of Crime Act.
"I am pleased with this morning's operation which was an example of successful partnership working.
"The types of offences we have been investigating present a risk to the public so this operation sends out a clear message that Thames Valley Police takes such offences seriously and will deal with any offenders robustly."