“The moment you do that... the notebook goes up in flames and all the evidence is completely destroyed.”
Current (電流, Denryū, lit. Electric Current) is the fourth chapter of the Death Note manga series.
Meanwhile, in his hideout, L meditates over the latest events. Originally, Kira's victims were reported to have died between 16:00 and 02:00, Japanese time, during weekdays, and the times were more varied during the weekends. L deduces that such hours match the times that a student would be out of school. Shortly after sharing this inference with the Kira Task Force, Kira changes the times of death so that they are spread throughout the day.
L is convinced that Kira became aware of the "student" theory, meaning that there is a leak in the Kira Task Force. Kira appears to want L to know this, but his reason is unclear. In any case, something is going to have to be done about the matter.
Meanwhile, Light makes his way to a DIY store in order to buy several items with which he will make a suitable place for hiding the Death Note from his family, while at the same time making it easily accessible for himself. Ryuk goes with him, invisible to anyone else.
Ryuk is puzzled. Since Light's father, Soichiro Yagami, is the head of the Kira Task Force, Light can obtain information on the progress of the investigation. What's more, Light can even hack his father's work computer without leaving a trace. With these advantages, he ought to be covering his tracks, but instead, he is leading L to realize that there is a leak, which is even more of a giveaway than the "Kira is a student" issue.
Light explains that it is all part of a long-term plan to get rid of L. Publicly, L and the police are working together in order to capture Kira, but Light doubts that the officers enjoy working with a person whose real identity is unknown even to them. If L investigates the Task Force in order to find the source of the leak, then this will further fuel the resentment and divide them. Furthermore, Light believes that the police may actually try to find L and discover his real name and appearance. When this happens, Light will be able to kill L!
At the offices of the Kira Task Force, three of the detectives working on the case approach Soichiro Yagami and hand in their resignations. They insist on being assigned to other cases, or they plan to leave the police agency altogether. It has been established that Kira can kill from a distance through some supernatural power. L has also asked the Task Force to find out if the names and faces of Kira's victims were made public prior to their deaths, and this has also been confirmed. If he is ever caught, Kira faces the death penalty for mass murder. Thus, it is logical to assume that he will kill those hunting for him. The three officers are concerned for their lives and those of their families and are leaving the Task Force.
As they leave, other detectives mutter that they may have a point. L's real name and likeness has never been made public, and he is likely to continue in this fashion and only communicate through his computer. Police officers, on the other hand, have to make their names and faces known as part of their duties and are sitting ducks.
L witnesses this scene on his computer, which is linked to cameras in the Task Force office. He, however, is simply satisfied with the fact that Kira needs to know the name and face of his victim before he can kill him.
In his room, Light has set up a more secure hiding place for the Death Note, based on the tests he carried out in the abandoned building. In a drawer in his desk he can place the Death Note on top of a thin plastic bag full of gasoline. Also in the drawer are pieces of metal attached to electric wires which link to the plastic bag and a small explosive device. This is covered by a false bottom that also has a piece of rubber that keeps the pieces of metal apart.
To demonstrate the effectiveness of the secret compartment to Ryuk, Light takes an ink cartridge out of a ball point pen. In order to access the Death Note, he simply has to push the ink cartridge through a small hole in the bottom of the desk drawer. This pushes the false bottom up and, replacing the piece of rubber as the drawer lifts, keeps the pieces of metal from touching and igniting the bag of gasoline. If Light is ever discovered and his room searched, simply lifting the false bottom out of the drawer will cause the pieces of metal to connect and send an electric current to a device connected to the bag of gasoline. This will start a small fire that will destroy the Death Note. If this happens, Light can claim that it is just an extreme way of destroying a very private diary. He considers a small house fire to be much less dangerous than someone finding the Death Note in his desk.
From his hideout, L has contacted Steve Mason, the Director of the FBI, the leading law-enforcement agency in the United States. L asks Mason to send agents to Japan in order to carry out a discreet investigation into the source of the leak in the Kira Task Force. The agents are to investigate the members of the Task Force and their close friends and families and thus hopefully find Kira.
- L contacts the FBI for help with the Kira investigation.
- Light hides the Death Note in a hidden compartment in the bottom of a desk drawer.
- Light reveals to Ryuk his plan for getting L and the National Police Agency to work against each other.
- Three police officers working on the Kira case turn in their letters of resignation.
The chapter title "Electric Current" is about the hiding of the Death Note and how an electric circuit is set to destroy it in case of its discovery. Tsugumi Ohba said that he considered "Current," "Destruction," and "False Bottom." In the end, he believed "Electric Current" was the best choice.