Johannesburg, South Africa (CNN) -- An American aid worker died from a gunshot wound suffered in the southern African nation of Lesotho, the Peace Corps said in a statement.

Peace Corps volunteer Thomas Maresco, 24, died in the country's capital, Maseru, on Friday.

"The deceased was attending a farewell function at the Maseru Sun Cabanas Hotel ... he and a female friend decided to return to the center on foot even though their vehicles were waiting outside the Hotel," Inspector Lekhotla Mojete, of the Lesotho police, told CNN in a phone interview from Maseru.

"The area the hotel is in is very safe -- with not much crime, but we think they were observed leaving the hotel on foot and when they were returning, (an) assailant was waiting outside the Hotel," Mojete said. "The stranger started making demands of them, which they didn't fully understand and (the assailant) then shot the deceased."

He said the woman accompanying Maresco rushed back into the hotel to get help, but police were unable to find the gunman when the arrived on scene.

"We believe this was a robbery," Mojete said.

A description of the attacker was provided to law enforcement officials by the woman. No arrests have been made yet and an autopsy was scheduled.

"Tom was an exceptional volunteer, leader, teacher and coach -- he was an integral part of his host community where he shared his passion for teaching, music and sports," said Aaron S. Williams, the Peace Corps' global director.

"We are deeply saddened by this tragic event, and I ask that you keep Tom's family, and our volunteers and staff in Lesotho in your thoughts and prayers."

The statement said that Maresco is from Port St. Lucie, Florida. He taught secondary education in the highlands district of Thaba-Tseka since November 2009. Maresco was scheduled to serve until January 2012.

Maresco's work also involved HIV awareness in the communities he served, according to the Peace Corps.

Peace Corps has 91 volunteers in Lesotho. More than 2,100 Americans have served as Peace Corps volunteers in the nation since 1967.

The tiny country in southern Africa is roughly the size of Belgium or the U.S. state of Maryland, according to the Peace Corps. Its border is completely surrounded by the nation of South Africa.

CNN's Les Neuhaus contributed to this story.