Gift of the Givers says it's awaiting information from their Mali contact to give possible clarity on the future of South African Stephen McGowan, following the release of Swedish national Johan Gustafsson.
"I'm very pleased to announce that Johan (Gustafsson) has today been able to return to Sweden and be reunited with his family", Foreign Minister Margot Wallstrom told reporters late Monday as she showed a picture of Gustafsson surrounded by his family after he arrived home.
The Swedish foreign ministry provided no details about McGown's fate.
"I have already spoken to Johan and he was in good spirits and overwhelmed by everything that's going on", Wallström told Swedish radio, saying she would hold a press conference later in the evening.
McGown, 69, was remembered during a church service on June 2 at which mourners recalled her lively demeanor but also the emotional toll that the abduction of her son had over years of uncertainty and reports of ransom demands.
Sweden's former Foreign Minister Carl Bildt tweeted after his release: "Extremely gratifying that Johan Gustafsson is free". Gustafsson was flown back to Sweden where he arrived Monday afternoon.
The trio were kidnapped by a group of armed men on the terrace of their hotel along with several other Westerners, including Mr Rijke's wife who managed to escape. Rijke had been freed in 2015 by French special forces.
The kidnapping of Gustafsson who Wallstrom said was the longest-held Swedish kidnapping victim "in the modern history of Sweden" took place in November 2011 as Islamic extremism was gaining a foothold in northern Mali.
Goran Gustafsson, Johan Gustafsson's father, would not confirm or comment the information to Swedish news agency TT.
The group was among many jihadist factions who took control of the north of Mali in 2012, before a French-led military operation began in January 2013 and the groups were removed.