Radio Liberty journalist Ogulsapar Muradova has died in prison in Turkmenistan with reported injuries to her head, the station says.
Ms Muradova was jailed in June
A relative reported the news after family members were asked by officials to identify her body in a mortuary in the capital, Ashgabat.
Her children are quoted as saying the body has "marks on the neck" and a "large wound" on the head.
Turkmen officials reportedly said she had died of "natural causes".
Liberty's Turkmen Service correspondent was detained in June, along with several human rights activists.
The radio station says no initial reason was given for her detention, but she was convicted on 25 August on charges of illegally possessing ammunition.
Turkmenistan is effectively a one-party state run since Soviet times by Saparmyrat Niyazov, and has no independent media.
Liberty, or Radio Free Europe/Radio Liberty as it is officially known, is a US-funded broadcaster with a stated mission to promote democracy in the former USSR and other regions.
Liberty says it was alerted to Ms Muradova's death by a member of her family who did not wish to be named.
Security officials at the mortuary assured the family that she had died of "natural causes" and they denied any wrongdoing.
After viewing the body, her relatives refused to sign a discharge form and left.
However, relatives later went back to the mortuary and demanded an independent medical examination, according to the Turkmen Helsinki Foundation (THF) human rights group.
"Morgue employees started threatening them," a THF activist said.
The time and circumstances of the journalist's death are unclear and it is also not known in which prison she was held, Radio Liberty says.
Tajigul Begmedova, head of THF, said Ms Muradova had been in excellent health before her arrest.
"Only after she was arrested she started asking for medicine," she was quoted by Liberty as saying.
"We then said it was strange that a healthy person should have health problems all of a sudden."