A spokesman for Polish police, Mariusz Ciarka, told private broadcaster TVN24 that the suspect had confessed to the crime.
The murder in the south of the country last week left people shocked and looking for answers. Police vowed to pull out all the stops to capture the murderer of 10-year-old Kristina.
Officers on Sunday announced the apprehension of a 22-year-old suspect, who subsequently faced charges of aggravated murder.
Officers told a news conference that they had received hundreds of tips after they asked the public for help in identifying the perpetrator.
These included recordings from dashboard cameras made available by drivers who happened to be passing near the scene of the crime.
The girl was on Thursday found dead with stab wounds in a forest some 6 kilometres from her home in the village of Mrowiny in the southwestern Lower Silesia province.
Investigators said she died of stab wounds to the chest and neck and that the murder had all the hallmarks of a sex crime.
As investigators worked on the case, many parents in the neighborhood were staying on the safe side, not sending their children to school.
On the fateful day, the girl reportedly left school at around 1 p.m. and was seen walking home a kilometre away. She was last seen alive just 200 metres from her house.
Police said they were leaving no stone unturned to apprehend the killer, with an exceptionally large number of experienced officers and prosecutors deployed to work on the case, according to Marek Rusin from the District Prosecutor's Office in the town of Świdnica.
Investigators and prosecutors were pinning special hopes on drivers using dash cams.
Justice Minister Zbigniew Ziobro said on Sunday that the person responsible for “this heinous crime” “will not escape punishment.”
"Anyone who harms children in such a ruthless way must be prepared to face the most serious consequences,” Ziobro said in a statement.
A throng of people stood for several hours outside the prosecutor's office in Świdnica where investigators questioned the suspect on Sunday evening.
Some people shouted threats against the suspect, state news agency PAP reported.
Source: PAP, TVN24, Gazeta Wyborcza