A gang of rogue traders conned elderly people out of more than £1 million by overcharging them for shoddy building work, a court has heard.
The group, who operated around Clacton and Colchester in Essex, targeted at least 18 victims between 2009 and 2013. Many lived alone, had dementia or were seriously ill.
Police and trading standards officers said there are likely to have been many more victims who were never identified.
Prosecutor Andrew Shaw said the men - led by ringleader James Brown Snr - "inveigled" their way into the victims' lives and discouraged them from talking to concerned relatives and neighbours as they pressurised them into handing over life savings.
Once they had found suitable targets - often by checking bank statements to assess their assets - the gang went back time and time again, demanding further cash as they "mined" their accounts, Chelmsford Crown Court heard.
Mr Shaw said: "These defendants operated as a group of rogue traders - builders who cold-called vulnerable elderly people and persuaded them to part with substantial sums of money for unnecessary building works or, where the work was justified, demanded extortionate sums of money.
"These cannot be the only victims of this gang and a conservative estimate is that they obtained at least £1 million."
Six men, who traded as East Coast Builders, Complete Building Services and AJ Builders, have admitted various charges linked to the fraud and appeared for sentencing today.
Judge John Dodds, who is expected to pass sentence later this week, commented: "It seems that once they got their claws into their victims, they would not let go."
Among the victims was 87-year-old Grace Gibbs, known as Gladys, who was widowed and suffered from bladder cancer.
She lost at least £123,000 as a result of unnecessary and often duplicated work on her home in Clacton, Mr Shaw said.
Helen Reeve Smith, who suffered from dementia and died last year aged 93, was invoiced for work totalling £30,000 and handed over £10,000.
James Brown Jnr, whom one victim dubbed "Smarmy Jim", and fellow gang member William Brown were both caught on CCTV in a local bank with Mrs Reeve Smith as she withdrew money just days before being sectioned under the Mental Health Act.
Christopher Ramsay, 58, who lived alone and was described as vulnerable, was initially quoted £650 for some bathroom tiling which was carried out to a poor standard.
He eventually handed over about £15,000, much of which was withdrawn after James Brown Snr drove him to cash-points.
Another victim, Kenneth Petford, was "groomed" into handing over £81,000 - his entire life savings - after one of the gang cold-called him and offered to power-wash his patio before convincing him further work was needed.
William Brown, 49, of Friday Wood Green, Colchester, has pleaded guilty to by false representation, conspiracy to convert criminal property and fraud
James Brown Jnr, 21, of Oak Road, Tiptree, admitted conspiracy to commit fraud by false representation and being involved in money laundering.
Peter Biddle, 66, of Bromley Road, Ardleigh, admitted fraud against three victims and converting criminal property.
Van Purdy, 60, of Bromley Road, Ardleigh, admitted conspiracy to convert criminal property
James Brown Snr, 45, of Duffield Drive, Colchester, admitted conspiracy to commit fraud by false representation, conspiracy to convert criminal property. fraud relating to loans, and two counts of fraud.
Anthony Symes, 59, of Clacton Road, Weeley Heath, admitted fraud against two victims and converting criminal property.
The case will continue tomorrow.