A Budapest court ordered an Irish man detained on suspicion of killing in a 31-year-old US tourist, whose body was found in woods in Hungary, it said on Monday.
Mackenzie Elizabeth Michalski, a nurse from the US state of Oregon who was on holiday in Hungary, was reported missing on Tuesday after she failed to return from a night out.
Her body was found in a wooden area near Lake Balaton in western Hungary.
The 37-year-old Irishman suspected of killing her led police to the area after his arrest on Thursday.
Police had identified the man after reviewing security footage from several nightclubs in central Budapest's nightlife district.
A Budapest district court said it had decided at its weekend session to order his detention for one month.
Police said the man, who has been only identified by his initials L.T. M., confessed to the killing, insisting it was accidental.
Police believe the suspect, who arrived in Budapest in October, met the victim at a nightclub, took her to a rented apartment, and killed her during "intimate intercourse".
"At present, it is not possible to establish exactly how the victim was killed and this is the subject of the ongoing investigation," the court said.
Internet searches
After allegedly killing Michalski, the man then cleaned the apartment, put her body in a freshly bought suitcase, and drove it in a rented car to Lake Balaton, police said.
The suspect is alleged to have made several internet searches, including on whether pigs eat dead bodies, the presence of wild boars around Lake Balaton, and the reliability of Budapest police.
The Irish foreign ministry told AFP it "is aware of this case and is providing consular assistance".
"As with all cases, the department does not comment on the specific details of individual cases," it added.
After Michalski went missing, one of her friends set up a crowd-funding page to raise money for the search and to help her family.
Michalski's parents traveled to Budapest in the hope of bringing their daughter home but learned en route of her death.
They attended a candlelight vigil in her memory near the US embassy on Saturday, thanking those who tried to find their daughter.
More than $40,000 have been raised in donations, according to the crowd-funding site.
The money will now be used to cover the cost of "travel and funeral arrangements along with any costs associated with ensuring justice for Kenzie".