Czech police have arrested a hospital worker suspected of having killed seven patients and of an attempt to kill another 10, officials said Sunday.

Regional police chief Petr Pribyl told reporters that the man, who had served as a nurse in a hospital in Havlickuv Brod, some 100 kilometers (62 miles) southeast of Prague, was arrested on Saturday.

Pribyl said the man confessed to the killings, but his motive remains unclear.

Police investigator Milan Justa said, however, that euthanasia was apparently not involved.

The suspect allegedly injected the patients with a drug which caused massive bleeding, chief doctor at the hospital's resuscitation department, Pavel Longin, said.

"The patients, who were recovering from serious accidents or surgeries, should not have received any (of the drug), but they got a high dose," he said.

Longin said the man, who had been working in the hospital over the last six years, was fired in September and subsequently police were informed. He said the first unusual deaths were recorded at his department in May.

The suspect, 30, was charged with murder and attempted murder, and is facing 15 years in prison if convicted. He can, however, receive a life sentence, an extraordinary punishment in the Czech Republic.

Click here for more news from Europe.