PARIS (REUTERS).- Pablo Picasso was both hugely prolific and famously generous with his work, but was he enough of a free spirit to give hundreds of his early works -- an invaluable collection -- to his electrician?

That question lies at the heart of a court case over the origin of 271 Picasso works -- a treasure trove of original sketches, paintings and collages that was unknown to the art world a few months ago and unveiled for the public on Monday.

Experts have yet to appraise the full collection, which has been placed under lock and key after a judicial appeal by Picasso's heirs. But there is little dispute so far over its authenticity. The works, many of which belong to the artist's Blue and Cubist periods, could fetch more than 60 million euros ($79 million) at auction.

More mysterious is how such an extensive collection could have wound up in the hands of a retired electrician in the south of France who once worked for the Picasso family, or why he chose to hold onto it for so many decades.

"We have questions, legitimate questions about where the paintings came from," Claudia Andrieu, legal counsel for the Picasso Foundation, told Reuters Television. "We are discovering new pieces, completely unknown pieces that had never been printed in any book."

The mystery began when Claude Picasso -- son of the artist and head of the foundation named after him -- received a letter from a man who said he owned original Picasso pieces and wanted to have them verified for authenticity.

Picasso convinced the man to bring the collection to Paris, saying he would be unable to verify it from photographs. The man arrived by car with the paintings in a suitcase and laid them out on a table.

"I felt a great surprise, naturally, lots of emotion at the discovery of pieces with which we were not familiar. But also a deep disturbance," he told French daily Liberation. "Many of these pieces were not dated, which means they never should have left the studio."

HEIRS UNCONVINCED
The man in question was Pierre Le Guennec, an electrician in his seventies who worked on Picasso's property in the south of France during the 1970s. He told Reuters Television that Picasso's wife gave him the artworks.

"It's Madame (Picasso) who gave them. But if Madame gave them, Monsieur was aware of it. She wasn't going to do it just like that, was she?" he said, speaking through a gate in front of his property. "What did you want me to do with them? ... They stayed in a box with other boxes that I have, from my job."

Yet Picasso's heirs were not convinced.

While the artist was known to dash out sketches on napkins at restaurants and make spontaneous gifts to friends, he would not have separated with such a large store of work, his son told Liberation. "It doesn't hold up, frankly," Picasso said.

Andrieu of the Picasso Foundation said that Le Guennec had changed his story many times, first telling them he had received the paintings from Picasso himself, then Picasso's wife, and alternately in a box or a trash can.

Questioned by the police, he said the paintings were given to him by Picasso's wife, who died in 1986. Le Guennec denied stealing the paintings and told RTL radio he decided to ask about their value as a possible inheritance for his children.

Unwilling to risk losing the works, Picasso's heirs successfully appealed to a judge to have the works placed under lock and key, where experts can study and care for them.

Among the works are nine extremely rare Cubist collages, a watercolor from Picasso's Blue period, several painted hand studies, some 30 lithographs and over 200 drawings, as well as portraits of the artist's first wife, Olga Khokhlova.

"Mr. Picasso is only interested in the history of art," Andrieu said. "We got the pieces secured, and now it is for the judge to determine how the pieces were obtained."

(Writing by Nick Vinocur, editing by Paul Casciato)