On January 1, 2012 Professor Kim Nando announced on his Twitter that "I’m currently ripping my hair out over writing the lyrics for SHINee’s new song."
Cosmetics brand Etude House released a video clip featuring Shinee as their endorsement models on January 17, 2012. In the video Shinee perform a song endorsing Etude House's new skin care line, Skin Malgami.
On January 31, 2012 it was announced that Shinee would release a live album on February 1st. The album contains the songs from theOlympic Gymnastics Arena on January 1st and 2nd, 2011 on their concert tour The 1st Concert "Shinee World". The album includes versions of "Juliette", "Ring Ding Dong", "Lucifer" and each member’s solo stages; Onew’s "Nessun Dorma", Jonghyun’s "Girls", Key’s "My First Kiss", Minho’s "OMG" and Taemin’s "Romeo + Juliette".
Shinee made their long awaited Korean comeback a year and five months after the release of Hello, with the announcement of their fourth mini album, entitled Sherlock. SM Entertainment stated that this comeback will be "world-class level with the best quality music, performances, and style" while "the album will contains songs of various genres with the members’ upgraded singing abilities and unique vocals". On March 8, 2012 the teaser photos of the members were revealed, starting with Minho and ending with Jonghyun on March 12.
On March 18, 2012 a teaser for Shinee's "Sherlock" music video was released on SM Entertainment's YouTube channel.
Sherlock, the digital version of the album, was released online through various online music sources, such as Korean music portals andiTunes, on March 19, 2012.After the album was released, their title song “Sherlock” achieved a real-time all-kill and maintained the #1 spot on various music charts. Shinee also gained a lot of attention in global music charts, such as in the United States, Canada, United Kingdom and France, and achieved 8th place on the iTunes Top Albums chart. They also reached 1st position on the Japanese, 6th on the Swedish, 9th on the Canadian, and 10th on the Mexican iTunes Chart.
The physical copies of the Sherlock album was released on March 21, 2012 in South Korea.
On March 22, 2012 Shinee's music video for their title song "Sherlock" was released on SM Entertainment's YouTube channel.Hours later Shinee made their return on Mnet's M! Countdown where they performed "Stranger" and "Sherlock".
On 27 March, 2012, Shinee's "Sherlock (Clue + Note)" was the #1 song on Music Champion.A few days later, Shinee received the #1 award for the same single on M! Countdown and Inkigayo.
On April 2, 2012, EMI Music Japan announced that Shinee will release Japanese version of "Sherlock" as their fourth Japanese single on May 16, 201