Development Following the success of his first film
Sathuranga Vettai (2014), director
H. Vinoth was keen to make a sequel to the film starring either
Suriya or
Ajith Kumar, but their reluctance meant that he moved on to work on a different project based on the
Operation Bawaria case. He stated that he had the idea of making a film on the case before he made
Sathuranga Vettai but had forgotten about it until he opened a food parcel, which was coincidentally covered with a newspaper article narrating the events of the operation and the incident subsequently inspired him to work on the script. Initially, planned as a road-trip film, the script was later evolved into a full-fledged police story revolving around the entire timelines of the operation and the events happened. Karthi expressed his immediate interest in working on the film, and recalled that he had first heard about the case while he was working on the making of
Siruthai (2011). The film was officially titled as
Theeran Adhigaaram Ondru in December 2016, with
S. R. Prabhu's
Dream Warrior Pictures agreed to produce the film in co-production with
Reliance Entertainment which had distributed the film. Speaking about the scaling and production of the film, H. Vinoth said that "it is a bigger film than
Sathuranga Vettai. That film, was just 10% of the original vision he had executed and planned to construct the six chapters of the film, with each chapter set within a specific geography, a dialect and a colour tone, which he had given up due to budget constraints". In this film, he had planned to shoot in original locations instead of cheating terrains in Chennai where they experience all that characters go through. Vinoth said that the producer gave full freedom on the filming without having thoughts on the film's budget. Karthi plays the titular character Theeran, modelled on the Tamil Nadu
Director General of Police S. R. Jangid, who led a special team to track down the main criminals involved in
dacoity as a part of the Operation Bawaria case. Interestingly, while compared to his brother,
Suriya's character Durai Singam in the
Singam franchise, Karthi said that "he has a command over things and he can reprimand anyone he wants", but referred the titular role as "an upright cop who goes about his work in a tactful manner" and is true to the original character despite tweaked. Rakul Preet Singh was signed to play the leading female role in the film. Talking about her character, Karthi said that "she has a nice and meaty role in it and would bring the much-needed relief in the film".
Bose Venkat was also selected to portray a police officer in the film, with the actor stating that the role gave him "a new dimension and a new identity". Telugu actor Narra Srinivas made his debut in Tamil cinema by playing a police officer.
Sathyan Sooryan was selected to handle the cinematography for the film, while
Dhilip Subbarayan, Kathir, Sivanandeeswaran were signed to handle the stunt, art departments and editing respectively.
Filming . In December 2016, a
photo shoot for the film was held at Balu Mahendra Studios in
Chennai with fashion photographer
Venket Ram capturing the stills of Karthi's look in the film. The shooting of the film kickstarted on 17 January 2017, with major sequences being shot in Chennai, and the team later headed to North India for filming several sequences. In mid-February 2017, the team headed to Rajasthan for shooting action scenes and the schedule went on for 40 days. Later, another 40-day schedule was held in Bhuj in mid-March 2017. To make the film as authentic as possible, Vinoth actively hired artistes from the regions and insisted on shooting in such locations, rather than replicating the terrains in Chennai or in studios. As the film takes place for more than a decade beginning from the 1980s, Vinoth had to shoot at well-developed places, instead of constructing sets as Vinoth said that "the storyboard has nearly 150 sites and it is impossible to construct sets in many locations, as a result went on a location scouting for many places which took a long time". On filming a chase scene involving two buses on a highway in Bhuj, Karthi said that "the exposure to the harsh sunlight became unbearable that he was literally under the verge of developing sun stroke". While another sequence featuring Karthi riding a horse in a river bed was filmed at Rajasthan-Gujarat border, the female horse named Chandini ran for two kilometres without break before finally stopping due to exhaustion. Karthi said that "the horse was only used in enclosed spaces, so when, the film was shot in a wide area and exposed to such freedom, the horse just began to run". The team also encountered sandstorm while shooting for the film, where a crane toppled over and drone cameras got damaged; the locals asked the team to cover themselves with blankets and patiently wait till the storm subsided. A huge set was erected in Rajasthan for few sequences in the film. In April 2017, an item number featuring actress Scarlett Mellish Wilson at
Jaisalmer Fort in Rajasthan, with the song being choreographed by Brindha. In mid-June, the team returned to Chennai to shoot the final schedule of the film which took place for a month. As of late-June, the team had completed more than 95% of the sequences, and needed 3–4 days, to complete the entire shoot. With the patchwork scenes being completed, the team wrapped the shooting of the film by mid-July 2017.
Post-production Post-production of the film simultaneously began during the final schedule of the shoot. Karthi completed dubbing for the film at the same time. The animation sequence about the backstory of Bawaria was headlined by R. Senthil Kumar and S. Jayachandran of Hybrid Studio, a Chennai-based animation company. Vinoth consulted and hired the team after eventually working for
Sathuranga Vettai (2014). He gave the script quite early, as it had scope for animation as it had a couple of portions that involved history. Jayachandran used the painting style for one portion and a graphic novel approach for the pre-interval sequence, with the primary use of colors — black, white and red — since blood was the theme of the film. The painting style that was the more complex one which had demanded more resources and concentration for the team. The two-and-half minute sequence had 4,000 frames with each frame being painted individually. So the animation team hired ten students from Government College of Arts, and were taught to paint the frames digitally. The process completed within one-and-a-half months, as compared to manual painting that may take a long time. The animation and production of this sequence went on for six months. == Soundtrack ==