How long can Cyprus police prevent someone from travelling?

Hello - I would like to know for how long the police in Cyprus can hold someone's pport and prevent a person from travellling overseas. Someone we know was taken in for questioning last November and subsequently released without charge. The culprit has never been caught. Meanwhile, he says the police have his pport and he can not travel abroad. He says they can keep the pport for up to six months. This happens to suit his agenda so am wondering if this is the case or he's just using it as an excuse (long story!) Thanks