Police have laid fresh charges against a man accused of trying to extort cash from several Sydney families.

Detectives attached to State Crime Command’s Robbery and Serious Crime Squad formed Strike Force Darly to investigate a string of reports of threatening mail being received by families across the metropolitan area.

In each case, the victims received letters demanding cash and threatening violence against their children if payment wasn’t made.

The 43-year-old Quakers Hill man is currently before the courts on charges of demand property with menaces (16 counts) and malicious damage (three counts).

As a result of further information received, he was re-arrested by strike force detectives at his home about 11am today.

The man was taken to Quakers Hill Police Station and charged with demand property with menaces with intent.

He was refused bail to appear in Penrith Local Court today.

It will be alleged that in April last year, the man extorted $50,000 from a Sydney couple after sending them a threatening letter.

Investigations are ongoing.

Meanwhile, police have issued the following safety tips:

• If you receive a threatening letter demanding money, contact police immediately

• Do not disclose any personal details to the persons outlined in the letter
• Do not make any payments
• Do not reveal any account details, ie PIN numbers, or account names or numbers
• Contact police immediately to report the incident.

Anyone who receives similar mail is urged to contact Crime Stoppers on 1800 333 000.