Death Note is similar to a Indian Bollywood movie called Darr (1993). I believe the person who wrote or made Death Note never saw the movie Darr.
Tell me if they are similar.
In the movie of Darr, a smart, intelligent but shy and lonely guy name Rahul which corresponds to Light chases after a girl name Kiran. Kiran is lover of Sunil which corresponds to L, who is also extremely intelligent.
Rahul main purpose was to be with Kiran by killing Sunil without anyone suspecting it was Rahul. He thought after killing Sunil, Kiran would like him since he resemble Sunil. Sunil works in military under Rahul dad just like Light's dad work under L. Rahul makes constant phone calls to Kiran with another voice and stalked her but no-one knows who is stalking Kiran. From this, the chess game begins between Rahul and Sunil almost very similar to Death Note between L, Near and Mello and Light. Rahul becomes good friend with Sunil and get all the police investigation from his dad and Sunil.
Rahul get out-smarted and couldn't prevent Sunil and Kiran from getting Married. Sunil and Kiran decides to move somewhere else that one one including their parents knows the location that they are moving to. As they board the plane, Rahul follows them but at last minute Sunil and Kiran change the plane to another one, similar to Mello did to Light, where Rahul get stuck on the other plane.
Rahul kills his friend and hangs his body to stage suicide and put all the Kiran's pictures and letters on the table saying since Kiran got married he has no meaning to his life. Police and everyone concludes that person who has been stalking Kiran is dead but Sunil wasn't convinced that the stalker was dead. The purpose of this was to get Sunil to reveal his current address. It very similar to Light giving the Death Notebook to the business-man and business-man gets caught, so Light can be free. Rahul begins to gang out with Sunil and Kiran's family get the address of Sunil and Kiran's. After like one year, Sunil finally gave his family his whereabout (similar Light's captivit under L). Rahul get information.
Sunil and Kiran is living in Switzerland, Rahul travels to near them. Sunil and Rahul meets in Switzerland and Rahul asked to stay at Sunil's house. Sunil hear from his parents that Rahul was there couple of days ago and he didn't say that he was going to Switzerland and lot of things rahul told Sunil contradicted what his parents told him. Sunil begins to know stalker is Rahul. Sunil put some drugs in his drink to create drunkess and prevent him from thinking properly, he ask lot of questions to Rahul. Rahul admits to loving Kiran and being a stalker. Sunil went to get the call the police, when he came back he found out that Rahul was missing and so was Kiran. Sunil got Kiran a watch long ago that if she was missing, by clicking on the watch, Sunil can locate her from his watch; by doing so Sunil was able to locate her. She was in a boat, Sunil shoots Rahul to death and rahul died by saying the name Kiran.