New Delhi: A 30-year-old five-storey building housing a boys' hostel in a congested bylane in Satya Niketan near Delhi University's South Campus collapsed on Sunday afternoon, leaving five students dead and many trapped. Locals claimed that there could be between 30 and 50 people in the building at the time.ET BureauAuthorities, however, gave no figure for those trapped. Repair work was underway in the basement of the five-floor structure, which was used as a paying guest accommodation, when it collapsed at around 1.30 pm, a senior officer said. Several vehicles also came under the rubble as the structure crashed.The AIIMS trauma centre received 10 patients, of whom four were brought dead, and one later succumbed to injuries. Delhi chief minister Rekha Gupta on Sunday ordered a magisterial probe into the incident.