A respected council officer led a double life, dressing as a tramp to sexually assault schoolgirls in south London and Surrey, a court heard.
De Boise was known as "Mr Nice Guy" by his work colleagues
Anthony De Boise, a Wandsworth Council planning officer, dressed in scruffy clothes, lying in wait at beauty spots, Southwark Crown Court heard.
Over seven years he attacked six girls, all were left mentally scarred, perhaps for life, the court was told.
De Boise, 58, who admitted six indecent assaults, will be sentenced on Monday.
'Mr Nice Guy'
De Boise, of Holmbury St Mary, Surrey, was so well liked at Wandsworth Council they called him "Mr Nice Guy".
But between 1989 and 1996, he would leave his wife and two children at their home, put on a disguise and subject his victims to ordeals of pain and degradation.
The first attack in June 1989 took place in Coulsdon, greater London, when he forced a 13-year-old girl to carry out a sex act.
Two years later in Hinchley Wood, Claygate he attacked a 16-year-old girl as she walked her dog.
He returned three years later, pulling out a knife on a 15-year-old girl and telling her "I will kill you if you don't shut up".
The court heard she was subjected to a prolonged and degrading series of sexual acts after being taken into nearby woods.
Less than a year later he attacked two 13-year-olds - both ran through barbed wire to get away from him.
His last attack, was on a 14-year-old girl on Riddlesdown Common, Surrey, in June 1996.
A Crimewatch appeal failed to find him, as the description of a scruffy homeless man in sunglasses was at odds with his usual smart appearance, the court was told.
But 10 years after his last attack, he was caught after a relative accused him of stealing money.
The charge was dropped, but a DNA sample was taken and matched samples taken in the unsolved attacks.
Judge Nicholas Loraine-Smith said: "The horror described in the impact statements of those he attacked was glaring."
He said he wanted the weekend to carefully consider the appropriate sentence and would sentence De Boise on Monday.
Stephanie Farrimond, prosecuting, said all De Boise's victims had been left mentally scarred.
Most could not trust men, some could not bear to be alone. In one case the victim's parents had ended up on medication because of the emotional effects.
Gillian Etherton, defending, suggested that a change of diabetes medication may have been partly to blame, as well as work pressure.
"How else do you explain such behaviour for a man married for 30 years who has an exemplary working record and is very hardworking?" she said.