NICOSIA, Cyprus -- A Cypriot army captain on Monday tearfully apologized to the families of seven foreign women and girls for the "unjust pain" he has caused them after pleading guilty to a dozen charges of premeditated murder and kidnapping.

Reading from a prepared statement ahead of his sentencing later Monday, the suspect, Nicholas Metaxas, told a three-judge criminal court panel that he "doesn't have any clear answers" why he committed the killings and that he has "struggled" to figure out the "why and how."

The 35-year-old officer said his co-operation with police investigators was "the least" he could do to ease the pain he caused to the families of the victims and his own. Metaxas killed four Filipino women and a daughter of one of them, as well as a Nepalese woman and a Romanian mother and daughter.

"I cannot go back in time and undo what I have done," Metaxas, clad in a bulletproof vest, told a packed courtroom.

He asked authorities for a scientific panel to interview him in order to delve into his psyche and find the reasons for his actions in what's believed to be the east Mediterranean island nation's first serial killer case. He did speak of unspecified events in his past "decades ago" that he tried to forget.

Looking down throughout his court appearance, a state prosecutor said six of the victims died of strangulation while the seventh, of a massive head injury.