Suspected serial killer Charles Sobhraj was charged in Kathmandu on Wednesday with using a fake passport when he entered Nepal almost 30 years ago.
Charles Sobhraj denies having visited Nepal in the 1970s
The 59-year-old French citizen was detained three weeks ago on alleged immigration offences, but has also been questioned over the murder of two Western backpackers in 1975.
Sobhraj re-entered Nepal last month from France, where he had been deported after serving 21 years in a Delhi jail for theft and drugging tourists.
He is suspected of involvement in up to 20 murders in a number of countries across Asia in the 1970s.
Sobhraj, also known as the "Serpent" and the "Bikini Killer", appeared in the Kathmandu District Court to deny charges of using false documents.
The prosecution said he had entered Nepal in 1975 on a Dutch passport under the alias Henricus Bintanja.
Sobhraj said his current visit was his first to Nepal.
The charges carry a jail term of up to five years.
Police say Sobhraj will be kept in detention while further investigations are made into the immigration charges and also the murders of Laddie du Parr, a Canadian, and American Annabella Tremont in 1975.
India deported Sobhraj in 1997 after he had spent 21 years in jail
Sobhraj appeared in court handcuffed and wearing a handkerchief over his face.
He will return to court on Thursday.
Police said that they had recovered a 1975 hotel registration form matching Sobhraj's handwriting.
But Sobhraj's lawyer, Sanjeev Ghimire, argued his client could not be charged
under a 1992 immigration law for offences relating to 1975.
Despite allegedly confessing to an author a series of murders and thefts, Sobhraj has never been convicted of murder.
He is alleged to have preyed on backpackers in Thailand during the 1970s, often drugging them and stealing their cash and passports.
The killings became known as the Bikini murders after American pilgrim Jennie Bollivar was found dead in her bikini in the Gulf of Thailand.
By 1976, the death toll had reached double figures and Sobhraj was wanted in at least three Asian countries.
He was jailed in Delhi in 1977 for drugging and stealing from an entire busload of tourists.
Sobhraj has been keeping a low profile in France since deportation from India in 1997.