FOUR Melbourne teenagers have been charged with 68 counts of rape after the alleged gang attack of a girl in a suburban public toilet block.

Police allege three of the four youths followed the 15-year-old girl from a railway station through the streets of Sunshine and St Albans before snatching her dropped school bag and forcing her into the toilet block.

The youths, two aged 15 and two aged 16, each face 17 charges of rape and one of false imprisonment over the alleged attack on May 5, which a court yesterday heard took place that evening.

The girl's parents had reported their daughter to police as a missing person when she did not return home from school.

She was found crying at a neighbour's house about 8pm, a Melbourne Children's Court heard yesterday.

The youths, who are of African origin, cannot be identified because of their age.

A detective from the sexual crimes squad testified that the girl, who is also of African origin, was known to some of the youths through a homework club at a local library.

He said that three followed her through Sunshine, on and off a bus, through the train station and on to the train she was catching to St Albans to return home.

The girl was uncomfortable when the three sat close to her in the same group of seats. When she left the train, the youths followed her along Main Road East as she walked home, the court was told. She later began to run, and turned down a side street, but when she dropped her school bag, one of the teenagers seized it and refused to return it.

By this stage, the fourth youth had joined the others and they ran away with her bag - she followed, asking for its return because it had valuable items in it.

The detective told the court that the teenagers stopped at a public toilet block at the rear of the St Paul's Church in St Albans, where she was forced into a cubicle; one boy told her to remove her clothing and raped her.

The detective said the three co-accused kept watch.

The first youth left the toilet after allegedly raping the girl three times, the court heard. The detective said he was wearing a condom but removed it.

After he left, the three co-accused entered one at a time and raped the girl at least twice each, the detective said.

After the fourth youth left the toilet, the first re-entered the cubicle and the initial order of the four entering and raping was repeated, the court was told.

Between each of the teenagers allegedly raping her, the girl repeatedly asked to have her bag returned and that she be able to go home, but they refused.

The detective said the girl reported the matter that night to her parents, and then to police, and was taken to the Royal Children's Hospital.

The detective said the teenagers could also face stalking charges.

Police have opposed bail for the four teenagers, alleging they would be an unacceptable risk of reoffending and of interfering with witnesses.

One of the teenagers' mothers told the court her son told her when he returned home that night he had been with friends at the library.

The court heard the parents and families of the teenagers were supportive and respectful of the police and the investigation.

An assistant principal of the Catholic school that two of the youths attend said there would be discussions about whether they would remain there.

Three of the teenagers have been in custody since Friday. The fourth was remanded on Monday.

The bail application resumes on Friday.