Unicornのプロセスがkillできないです。

###困っていること
Capistranoでデプロイする際に以下のようなエラーがでてしまい、デプロイできなくなってしまいました。
Nginx + Unicornでrailsアプリケーションを動かしていて、それぞれ/etc/init.dに自動起動スクリプトを書いていたため、サーバーを再起動させてからデプロイしようとしたのですが、うまくいきません。

###発生している問題・エラーメッセージ
Unicornをsopさせたいのですが、うまくいきません。

[hoge ~]$ ps aux | grep unicorn | grep -v 'grep'
[hoge~]$

[Daiki@ip-10-0-2-218 ~]$ sudo /etc/init.d/unicorn stop
stop Unicorn
/etc/init.d/unicorn: 32 行: kill: (4082) - そのようなプロセスはありません

[hoge ~]$ sudo /etc/init.d/unicorn start
[sudo] password for hoge: 
Unicorn already started


00:26 unicorn:restart
      01 kill -s USR2 $(< /var/www/Vook/current/tmp/pids/unicorn.pid)
      01 kill:
      01 sending signal to 4082 failed
      01 :
      01 そのようなプロセスはありません
(Backtrace restricted to imported tasks)
cap aborted!
SSHKit::Runner::ExecuteError: Exception while executing as Daiki@52.198.21.134: kill exit status: 1
kill stdout: Nothing written
kill stderr: kill: sending signal to 4082 failed: そのようなプロセスはありません

SSHKit::Command::Failed: kill exit status: 1
kill stdout: Nothing written
kill stderr: kill: sending signal to 4082 failed: そのようなプロセスはありません
/Users/takayadaiki/projects/Vook/lib/capistrano/tasks/unicorn.rb:22:in `reload_unicorn'
/Users/takayadaiki/projects/Vook/lib/capistrano/tasks/unicorn.rb:51:in `block (3 levels) in <top (required)>'
Tasks: TOP => unicorn:restart
(See full trace by running task with --trace)
The deploy has failed with an error: Exception while executing as Daiki@52.198.21.134: kill exit status: 1
kill stdout: Nothing written
kill stderr: kill: sending signal to 4082 failed: そのようなプロセスはありません


** DEPLOY FAILED
** Refer to log/capistrano.log for details. Here are the last 20 lines:


 DEBUG [e906a1b0] Command: if test ! -d /var/www/Vook/releases/20170125061945; then echo "Directory does not exist '/var/www/Vook/releases/20170125061945'" 1>&2; false; fi

 DEBUG [e906a1b0] Finished in 0.084 seconds with exit status 0 (successful).

  INFO [f744d9da] Running $HOME/.rbenv/bin/rbenv exec bundle exec rake db:migrate as Daiki@52.198.21.134

 DEBUG [f744d9da] Command: cd /var/www/Vook/releases/20170125061945 && ( export RBENV_ROOT="$HOME/.rbenv" RBENV_VERSION="2.1.3" RAILS_ENV="staging" ; $HOME/.rbenv/bin/rbenv exec bundle exec rake db:migrate )

  INFO [f744d9da] Finished in 3.577 seconds with exit status 0 (successful).

  INFO [0223c969] Running /usr/bin/env ln -s /var/www/Vook/releases/20170125061945 /var/www/Vook/releases/current as Daiki@52.198.21.134

 DEBUG [0223c969] Command: ( export RBENV_ROOT="$HOME/.rbenv" RBENV_VERSION="2.1.3" ; /usr/bin/env ln -s /var/www/Vook/releases/20170125061945 /var/www/Vook/releases/current )

  INFO [0223c969] Finished in 0.148 seconds with exit status 0 (successful).

  INFO [09437040] Running /usr/bin/env mv /var/www/Vook/releases/current /var/www/Vook as Daiki@52.198.21.134

 DEBUG [09437040] Command: ( export RBENV_ROOT="$HOME/.rbenv" RBENV_VERSION="2.1.3" ; /usr/bin/env mv /var/www/Vook/releases/current /var/www/Vook )

  INFO [09437040] Finished in 0.127 seconds with exit status 0 (successful).

 DEBUG [07bf5446] Running [ -f /var/www/Vook/current/tmp/pids/unicorn.pid ] as Daiki@52.198.21.134

 DEBUG [07bf5446] Command: [ -f /var/www/Vook/current/tmp/pids/unicorn.pid ]

 DEBUG [07bf5446] Finished in 0.134 seconds with exit status 0 (successful).

  INFO [c30db33d] Running /usr/bin/env kill -s USR2 $(< /var/www/Vook/current/tmp/pids/unicorn.pid) as Daiki@52.198.21.134

 DEBUG [c30db33d] Command: ( export RBENV_ROOT="$HOME/.rbenv" RBENV_VERSION="2.1.3" ; /usr/bin/env kill -s USR2 $(< /var/www/Vook/current/tmp/pids/unicorn.pid) )

 DEBUG [c30db33d] 	kill: 

 DEBUG [c30db33d] 	sending signal to 4082 failed

 DEBUG [c30db33d] 	: 

 DEBUG [c30db33d] 	そのようなプロセスはありません

###試したこと
サーバーで手動で起動、停止を試みる

###補足情報(言語/FW/ツール等のバージョンなど)
より詳細な情報