The investigation into ex-Bosnian Serb army chief Ratko Mladic will be extended to anyone thought to have helped him avoid arrest for 16 years, Serbian President Boris Tadic has said.
Mr Tadic told the BBC anyone who protected him would be prosecuted.
Gen Mladic would be transferred to The Hague to be tried for war crimes, despite an extradition appeal by his lawyers, the president insisted.
Arrested on Thursday, he faces genocide charges over the 1992-95 Bosnian war.
Gen Mladic was declared fit to be extradited from Serbia to face trial, although his family and legal team say he is in poor health.
He was indicted in 1995 over the killings about 7,500 Bosniak (Bosnian Muslim) men and boys that July at Srebrenica - the worst single atrocity in Europe since World War II - and other crimes.
Relatives of Srebrenica victims welcomed the arrest as a relief.
However, some residents of Serb areas of Bosnia expressed regret, and in Gen Mladic's former command post, Pale, about 2,000 people protested against the detention.
Mr Tadic said the investigations would look at any help given to Gen Mladic by members of the Serbian armed forces or police, adding that he had been able to count on the support of what he termed "some people in the state system" over the years.
"In the next few days, we'll have a completed picture of what happened in the past two-and-a-half years, even more, in the past 16 years," he said. "And, for us, that is going to be very, very important."
The president added that while Gen Mladic had initially enjoyed considerable support from some officials, this weakened after the overthrow of Slobodan Milosevic in 2000.
He said efforts to find the former army chief were stepped up when he himself took office in 2004, but were often frustrated by his extensive family.
"He had many, many relatives, not only in Serbia but also in other regional countries - in Bosnia and Hercegovina, Macedonia and other countries," he said.
"That was making real difficulties in terms of investigating that case."
Earlier court spokeswoman Maja Kovacevic told reporters outside the court that Gen Mladic's health was good enough for him to be extradited to the tribunal.
He had refused to accept a copy of the tribunal's indictment, she added. After this, the court ruled that the conditions for his transfer had been met and he was given until Monday to appeal.
Defence lawyer Milos Saljic confirmed that an appeal would be submitted on Monday. The judge then has up to three days to consider it, though the BBC's Mark Lowen, in Belgrade, says the matter may be dealt with more quickly.
Gen Mladic's wife Bosiljka and their son Darko turned up at the court to visit him. Mr Saljic later said this was their first meeting with him in 10 years.
Darko told journalists his father was innocent and not in a fit state to be sent to The Hague.
Meanwhile Serge Brammertz, chief prosecutor at the UN International Criminal Tribunal to the former Yugoslavia, said he was considering putting Gen Mladic on trial together with former Bosnian Serb political leader Radovan Karadzic.
Mr Karadzic was arrested three years ago and has been on trial since 2009. Any joint appearance would mean lengthy delays in his proceedings, correspondents say, as it could take months before Gen Mladic is ready to go to trial.
Having lived freely in the Serbian capital, Belgrade, Gen Mladic is believed to have gone into hiding after the arrest of former Yugoslav President Slobodan Milosevic in 2001.
Serbia had been under intense international pressure to arrest Gen Mladic and send him to the Hague tribunal.
The government is now keen for a speedy extradition of Gen Mladic, whom Serb nationalists still regard as a hero, says our correspondent.
Gen Mladic was seized in the province of Vojvodina in the early hours of Thursday, reportedly as he went out into his garden for a pre-dawn walk.
He had two guns with him, but put up no resistance, officials said.
Serbian security sources told AFP news agency that three special units had descended on a house in the village of Lazarevo, about 80km (50 miles) north of Belgrade.
The single-storey house was owned by a relative of Gen Mladic and had been under surveillance for the past two weeks, one of the sources added.
In the latest revelations, police officials told the Associated Press that Gen Mladic had moved to the village two years ago. They also said he immediately admitted his identity when found.
AP quoted officials as saying no-one would receive a reward for his arrest, because police were not acting on a tip-off when they arrested him.