PALMA DE MALLORCA, Spain (Reuters) - The charity Proactiva Open Arms has filed a complaint, including of involuntary manslaughter, with the Spanish police against a cargo ship for failing to help migrants adrift on a destroyed dinghy in the Mediterranean.

The captain of the charity’s rescue boat said on Saturday he also plans to file a separate suit against the Libyan lifeguard.

The migrant rescue boat Open Arms docked in Spain on Saturday carrying the bodies of a woman and a four-year-old boy as well as one woman who was found alive floating on the remains of a dinghy off the coast of Libya last week.

The boat took four days to arrive in the Spanish port of Palma after finding the migrants adrift about 80 miles (130 km)off Libya’s coast after being abandoned by the Libyan coast guard, the charity said.

“We have filed a complaint against the captain of the (merchant ship) Triades for failing to help and for involuntary manslaughter and we’ll also do it against the captain of the Libyan patrol,” Oscar Camps, the Open Arms captain and founder of the NGO, said at a news conference.

Open Arms claimed the ship’s crew had seen the migrant dingy but had failed to provide help. Reuters could not find a way to contact the captain of Triades, which flies a Panamanian flag. The ship is currently moored in the Libyan port of Misrata, where officials could not be reached for comment.

The Libyan lifeguard also left the three migrants to float amid the shattered remains of the raft after the two women and the boy had refused to board their patrol ship, the charity said.

Libya’s coast guard disputed the account on Tuesday but offered no explanation for how the three migrants came to be stranded on the remains of the dinghy.

The Spanish charity operates in the central Mediterranean, one of the deadliest areas of the sea and favored by people smugglers operating out of Libya.

Charity boats have been locked out of Italian ports, the closest European landing point, since Italy’s new government vowed to crack down on illegal immigration from Northern Africa.

Open Arms found itself at the center of the European immigrant crisis at the start of the month when it rescued 60 migrants off Libya and brought them to Barcelona in Spain after being refused docking in Italy and Malta.