MUMBAI, Jan. 28 -- Omkar Shinde, the 27-year-old metal worker who killed a college lecturer in a crowded local train, says he experienced a sudden impulse to stab Alok Singh, 33, as he felt "insulted" and "embarrassed" by the deceased during their altercation over right of way in the train. Shinde stabbed Singh in the abdomen as he alighted from the train after it pulled into Malad station on Saturday evening. When Shinde asked Singh to move forward, to make sure they could alight from the coach, Singh said he couldn't as there was a woman in front of him. Shinde admits the two had argued but claims the deceased and his colleague, also a lecturer at NM College where Singh taught, had slapped him before he could climb down from the coach. Embarrassed at being allegedly slapped in front of women in the coach, he felt the urge to stab Singh, Shinde told the Government Railway Police (GRP) investigating the case. Police say eyewitnesses have not corroborated Shinde's account, that he was slapped, and are searching for eyewitnesses to find out what really happened. Meanwhile, police are yet to recover the murder weapon, a pair of tongs, allegedly used by Shinde. Police investigating the case said Shinde claimed he threw away the tongs while he was returning home but did not reveal where he tossed it. Shinde, who was employed in a metal workshop and jewellery unit at Grant Road, was carrying the tongs in his bag. The wound he inflicted was 5 inches deep, and Singh bled to death. On Tuesday, police searched for the murder weapon in Shinde's house in Kurar Village, Malad east, but in vain. "We took Shinde to his house and conducted a detailed panchnama," said a police officer. He said they also recorded statements of Sinde's family members and the RPF personnel who were with Singh as he sat on a bench at the railway station, before he was taken to Shatabdi Hospital in Kandivali west. Meanwhile, Western Railway (WR) is expediting the process of installing CCTV cameras inside local trains. Until now, the women's compartment was a priority but the railway is also focusing on the first class and general coaches. WR officials say they will install more than 12,000 cameras inside 1,500 coaches in local trains. These are high-end CCTVs that will not only have facial recognition but also video analytics. "We had an internal meeting to discuss the Malad incident. We will further strengthen our monitoring system for stations and trains. The installation will be completed within 10 months after the contract is awarded," said a WR official. At present, more than 3,000 CCTV cameras have been installed across suburban stations....