Gangland identity Roberta Williams has been arrested as part of an investigation into the alleged kidnapping of the producer of her proposed reality television program.

Williams, the widow of Carl Williams, was led away in handcuffs from her Strathmore home in Melbourne’s north-west on Wednesday morning according to Nine News footage.

Police confirmed the fraud and extortion squad raided five properties in Craigieburn, Greensborough and Strathmore as part of an ongoing investigation.

“This investigation centres on allegations of false imprisonment and extortion with threats to kill,” a police spokeswoman said.

“As the investigation is ongoing we’re not in a position to comment further.”

Williams, 50, was arrested along with two Greensborough men aged 24 and 27, and a 24-year-old Craigieburn man. They are assisting police.

The Age last month revealed Williams was being investigated over an alleged extortion and kidnapping plot following allegations she imprisoned and assaulted the producer of her proposed television show.

The producer alleged Ms Williams and five others attacked him in a Collingwood building and demanded money.

One of Ms Williams’ associates was charged last month with kidnapping, extortion and threats to kill.

The 36-year-old Princes Hill man was released on bail and will appear in Melbourne Magistrates’ Court in October.

The producer alleged the group forced him at gunpoint to ask relatives to transfer $17,000 to a bank account and then continued to demand further payments.

Williams is the widow of drug boss and convicted killer Carl Williams, who was bashed to death in 2010 inside Barwon Prison after making statements implicating former policeman Paul Dale in the 2004 murder of informer Terry Hodson.

-Rachel Eddie, The Age