By Karim Okanla BBC Sport, Cotonou

Samiou played in Benin's African Youth Championship loss to Nigeria

Police in Benin have launched a murder inquiry following the death of the country's under-20 goalkeeper Youssoufou 'Campos' Samiou.

Samiou died on Monday morning in a clinic in the Beninois capital Cotonou after being attacked by unknown assailants on a beach on Sunday night.

"We are looking for two or three men because it's not just one man who could have done this," Commissaire Constant Soso, the police official for Interpol in Benin, told BBC Sport.

"At this stage of our inquiry, we know that he was alone on the beach and that his mobile phone was stolen by his aggressors."

Nigeria beat youth hosts Benin

Samiou, who played in the hosts' 3-0 defeat by Nigeria in their opening Group A game of the African Youth Championship on Saturday, was near his team's hotel when the incident happened.

It is still unclear whether the attack was in connection to Benin's heavy defeat, which infuriated local supporters in the poor West African nation because a lot of money has been invested in the team's development.

The medical doctor who treated the young footballer at the Hubert K. Maga University Teaching Hospital said Samiou suffered a serious brain haemorrhage following the fracture of his skull.

"He fell into irreversible coma after they brought him to me," Dr Abderamane Abdou told BBC Sport.

We are looking for two or three men because it's not just one man who could have done this Commissaire Constant Soso

"The X-ray of his skull that came out of the lab on Monday clearly indicates that his chances of survival were very slim."

Reports in Benin suggest that Samiou received an anonymous call on Sunday night which lured him out of the El Dorado Hotel.

Security guards at the hotel said they did not know how Samiou managed to slip out of the hotel premises without attracting their attention.

Commissaire Soso told the BBC that security has since been stepped up at all playing venues and team hotels.

Nonetheless, the parents of Seidath Tchomogo, the Junior Squirrels striker who missed a penalty against Nigeria, are so concerned for their sons' safety that they have ordered him home.

Whether Tchomogo is still with the squad will become clear when Benin face the Ivory Coast in Cotonou on Tuesday afternoon.

In the day's other Group A game, Nigeria take on Mali.