Blizzard's Overwatch Twitter account has released an image of a "confidential" internal memo that shows off a brand new sniper that can heal, teasing that a new character may be coming to the popular hero-based shooter soon. Posted on 6 July, the tweet seems to be a reference to the much rumoured character named Sombra who, if officially revealed, would be the game's first post-release character.

The tweet features a blueprint image of a "Prototype Biotic Rifle," which hasn't been seen in the game before, designed by Swedish defender Torbjörn. Combining features of Mercy's Caduceus Staff and Soldier: 76's Biotic Field healing ability, the weapon will allow players to heal allies from a distance as well as potentially cause damage.

The blueprint also shows some sort of canister that can be deployed as well, which could be a healing grenade, ammo or something entirely different.

The image includes a conversation between Torbjörn Lindholm and Angela Ziegler, otherwise known as the healing character Mercy, who debate over the sniper's potential applications.

"As discussed, this is the proposed rifle that could be equipped by medics in the field," Torbjörn says. "Despite what my esteemed colleague will surely suggest, the application of her biotic technology is only intended to be used for healing."

Mercy, on the other hand, responds: "While Torbjörn has, as ever, put forth a very clever design for his latest weapon. I would like to remind everyone that my intention when agreeing to the development of different biotic delivery mechanisms was to save the lives of Overwatch agents and others in need of medical aid."

"With this latest proposal, it is clear to me that we are on the slippery slope to modifications that will inevitably result in a weaponized version of this technology: something that I have been completely opposed to from the beginning."

The recipients of the message, noted in the top left corner of the blueprint, are Jack Morrison and Gabriel Reyes, otherwise known as Soldier: 76 and Reaper, respectively.

The latest teaser comes amid a flurry of fan theories and speculation about the new sniper, Sombra (which means "shadow" in Spanish), being added to the colourful Overwatch roster based on several leaked details and hints within the game.

In the game, one of deadly assassin Reaper's voice lines is "Where is Sombra when you need her?" The name Sombra is also found in a Spanish newspaper in the Dorado map.

Fans have also speculated that Sombra is actually Ana Amari, the mother of Fareeha "Pharah" Amari and one of founders of Overwatch who is seen wielding a sniper rifle in Soldier: 76's Origin Story video. The official Brazilian Overwatch Twitter account seems to confirm that theory, listing "A. Amari" together with the Morrison and Reyes.

Overwatch game director Jeff Kaplan previously told Eurogamer that the team will add new Overwatch heroes one at a time for a while until "the game really stabilises".

He also mentioned that it was "not strange" that fans have already begun speculating about Sombra either, noting that gamers still haven't uncovered all of the hints regarding the new sniper.

"We have put a lot of hints, all over the game and out of the game, so I would say it's about time that people are concerned with who Sombra is," he said. "I hope they keep researching more and find more hints that are out there."

Overwatch is available now for PS4, Xbox and PC.