An interpreter accused of faking sign language at Nelson Mandela's memorial service has been admitted to a psychiatric hospital for treatment.

Thamsanqa Jantjie has claimed that he had a schizophrenic episode and saw angels descending on the Johannesburg stadium where his bizarre signing prompted consternation last week. The 34-year-old became the subject of worldwide mockery and was bombarded with interview requests.

South Africa's Star newspaper said Jantjie's wife, Siziwe, had taken her husband for a check-up on Tuesday at a psychiatric hospital, which determined that he should be admitted. "The past few days have been hard," Siziwe was quoted as saying. "We have been supportive because he might have had a breakdown."

Jantjie had an appointment for a check-up at the Sterkfontein psychiatric hospital in Krugersdorp, west of Johannesburg, on 10 December, the Star reported. But this was shifted after he was offered the job to sign at the Mandela memorial service, which was held on the same day.

On Friday Siziwe confirmed that her husband was in hospital and she did not know how long he would be there.

Jantjie has admitted to a history of mental problems and violent episodes in the past and that he had been a patient in a psychiatric institution for more than a year. He was discharged and started working after being medicated and monitored by doctors.

Sign language experts said his translations of eulogies at the globally televised service, attended by nearly 100 current and former heads of state and government, amounted to gobbledygook. The clownish performance, just feet from President Barack Obama and other speakers, raised questions over what security measures were in place.

Earlier this week the Associated Press reported that a cousin and three friends of Jantjie alleged he was part of a mob that accosted two men found with a stolen television and burned them to death by setting fire to tyres placed around their necks – a notorious vigilante tactic known as necklacing.

Jantjie never went on trial for the 2003 killings, while the other suspects did, because authorities determined he was not mentally fit to stand trial, the four told the AP. Jantjie has denied the allegations.

South African media have reported that he has also allegedly faced rape, kidnapping and theft charges. In his home province of Free State, local media have claimed Jantjie has impersonated a lawyer and traditional healer.

The South African government has admitted a mistake was made and Jantjie was not suitably qualified for the memorial service. It has started an investigation and apologised to deaf people for any offence it may have caused.

The African National Congress is investigating claims that some of its officials were directors of the company for which the signer worked.