Ukrainian authorities have formally notified jailed former prime minister Yulia Tymoshenko that she is a suspect in the murder of a businessman and politician in 1996.
The Prosecutor General's Office said on its website that Tymoshenko is suspected of "ordering and organising" the contract-style murder of Yvhen Scherban, his wife and two other people.
The move stops short of formally charging Tymoshenko, but indicates that charges are likely. Prosecutors have said for months that she was being investigated in the case.
Tymoshenko denies the accusations and says it is part of a broader campaign by her enemy, President Viktor Yanukovych, to keep her in prison and bar her from politics.
Tymoshenko is serving a seven-year prison term for abuse of office while negotiating a gas deal with Russia in 2009.