Brunner is shown as a man with a thick, blackish (or dark brown) beard that covers most the lower half of his face. Attached to it is his midlength, black and unkempt hair (probably hasn't been washed in a while) and deep blue eyes. His attire consistent with dirty blue jeans and a green/darkened white sleeveless shirt. He's later seen in just the jeans.
When first introduced as Dexter is "hunting" him, Brunner can at least be seen as someone who doesn't tolerate child molesters, until Dexter reveals under an unnamed alias that he was arrested for having an affair with a girl "who didn't know the meaning of implied consent". Brunner, with a face that looked to be defining the situation, then decided that Dexter could sit...meaning that Brunner at least has a personal understanding of people just like him (thus he's not all bad per say around other people, rather he's probably looking for someone just like him to talk to).
On top of this, he also thinks highly of his prison buddy Boyd Fowler, most likely because the two of them are sexual deviants of the same nature (which is why Dexter believed he was involved in Boyd's crimes at the time).
Of course, that just paints him out a pretty picture...as Dexter continues to talk with him it's clear that Brunner is more of a pig than anything else. While he talks like an ex-con with his "where'd you do time at?" and "that's a tough place to stay in..." attitude, he suddenly switches to a rapists persona when talking about "farm-fresh pussy" and what he planned to do with them. Eventually he goes into a speech about some blonde he had on "all-fours"...which sent Dexter into injecting him with the sedative right away.
From his past crimes, he can be seen as a very violent person who uses whips or otherwise to cause bloody scars on his victims (of rape) backs. It's possible he is very rough with how he abuses them sexually as well, thus deserving of his sentence and now living underneath a bridge.
As the story progresses, Lumen Pierce reveals that several men were involved in her abuse and torture other than Boyd Fowler. Lumen goes on to research possible perpetrators, eventually coming up with a face and name of a rapist who matches her situation perfectly, Robert Brunner. Dexter Morgan ends up doing a little research of his own on Brunner to find out what information he can, some of which is consistent with the wounds and patterns of assault used on Lumen (specifically the scars on her back). Dexter then pays him a visit in his newly acquired home...the Tunnel Bridge, a somewhat forced retreat for folks of his nature (rapists, molesters, gang members...etc.)
When Dexter finally locates Brunner, he is seen watching a sort of documentary on some location out of the states while drinking some alcohol and resting by a fire. Dexter approaches, to which Brunner assumes he's a pedophile and quickly writes him off as such...telling him that kid molesters stay by the tracks. Dexter quickly adopts a grizzled accent, acting like a truck driver that slept with a girl that had a problem with understanding "implied consent". Brunner keeps an eye on him for a second and then lets him sit down next to him, the two conversing on where Dexter (under an unknown alias) stayed whiled he served time and then about farm girls. Eventually Brunner speaks of a blonde (whom Dexter assumes is Lumen) that he had a little while back that was on all fours and how he treated her, this caused Dexter to inject him soon thereafter with sedative to put him out and ready for the kill.
As Dexter prepares to do the ritual (though improvised and most likely in the same Kill Room meant for Boyd Fowler), Harry protests actively to this kill as being an act of impulse rather than sticking with the code. Dexter argues back that it's right and that he is one of Lumen's attackers, that he fits the bill but Harry still begs to differ, stating that this ritual first has nothing to do with Brunner (especially the pictures of women that Boyd Fowler killed, which as we are shown was done merely by him alone at least at this point) and second, that he's on parole...which means that he most likely has an ankle bracelet (used to keep track of his location). Dexter quickly cuts the legging on Brunner's pants to discover the bracelet, which puts him into a bit of shock and causes him to drop his blade that was going to be used for the kill. He can't believe that he almost made another mistake...and this one would have cost him dearly, as that ankle bracelet might have made him if he wasn't careful. Dexter quickly brings Brunner back to underneath the bridge and pretty much dumps him out of his vehicle as fast as he can, driving back to his apartment (only to be greeted by a face he wouldn't like to see there... Joey Quinn).
The next day, Dexter tries to confront Lumen at her motel room but finds out that she had already left for the bridge...which causes him to run back in a hurry to catch up with her (because he knows she's intent on taking his life). As Lumen begins to wander the area looking for Brunner, it can be seen that she's really doing this in a starter's fashion...a lot of fear runs through her body and this kill will be shaky, if anything else. Lumen eventually locates her target, whom is now without his shirt and looking like he woke up from a hangover (most likely the after effects of the sedative in his system). It's unknown if Brunner will remember Dexter's face, but he doesn't seem to be in a hurry to find out what happened to himself...instead he just kind of wanders and even converses with another con while in her sights. Lumen kept a revolver with her and pointed it directly at him from a distance (which in itself provided a problem: first, her distance would possibly cause the shot to miss...especially using a magnum with her body type, the kickback would most likely force the bullet in any which direction. Second, the sound from the gun would alert every con in the vicinity and thus endanger her life even more than before...and third, she is taking no preventive measure in being caught here...the bullet can easily be traced back to the gun and there's likely a chance she'd be caught easily).
While she has trouble keeping aim, she eventually gets a clear shot of him but just before she pulls the trigger, Dexter intervenes and takes the gun from her, instructing her that he is not her target...that there is no possible way he could have been involved in her abuse. Lumen looks on in terror of what she might have done and in her mind, most likely marks him off her list. Brunner caught wind of the commotion that went on behind the pillar where she was stalking him...but went back amongst his business afterwards.
Robert Brunner is a serial rapist who is responsible for the rape of three women and a strict-abuser with a violent streak. He's not a killer by Dexter's standards and thus would not fit the code... much like the child molester who targeted Astor Bennett in a previous season (although Dexter did kill the latter in order to protect Astor).
- ↑ Season 5, Episode 5..."First Blood"