BBC drama -- The Cry (limited series)

[C C]

[...]

Wondered this, too - Alistair is a textbook narcissist so perhaps he took the photograph to mark “getting away with it.” What was your take on Alistair’s relationship with his mom?

It wasn't until the prosecutor brought up that Elizabeth hadn't visited him in Scotland (for ten years?) that I even wondered if I had been missing "signs" with regard to that relationship. When his mother suggested or hinted at a single person being involved (perhaps even referencing such as "him"), Alistair was quick to correct her that two individuals could be responsible ("two can keep a secret better than one" or something along that line, if my lousy memory is even half-correct). So his personal nature was apparently as well known to her as to his ex-wife Alexandra. No matter what developed, both remained (surprisingly?) sympathetic to Joanna.

[Leigha]

[...]

Wondered this, too - Alistair is a textbook narcissist so perhaps he took the photograph to mark “getting away with it.” What was your take on Alistair’s relationship with his mom?

It wasn't until the prosecutor brought up that Elizabeth hadn't visited him in Scotland (for ten years?) that I even wondered if I had been missing "signs" with regard to that relationship. When his mother suggested or hinted at a single person being involved (perhaps even referencing such as "him"), Alistair was quick to correct her that two individuals could be responsible ("two can keep a secret better than one" or something along that line, if my lousy memory is even half-correct). So his personal nature was apparently as well known to her as to his ex-wife Alexandra. No matter what developed, both remained (surprisingly?) sympathetic to Joanna.

Agreed. I think they had both been 'victims' of Alistair at one point or another. His ex wife still dealt with bouts of abuse from him, like when he stopped over her house to gaslight her. He seemed like a true misogynist in that he hated women, even his own daughter. It appeared like he cared, but for him to put her through that, and his ex wife, his mom, Joanna...it all pointed to misogyny, a loathing of women where the guy pits them against one another. He seemed amused when his ex wife was hurting/jealous. Even his mom appeared uneasy around him. I thought the series covered a lot of ground for just four episodes! Oh...one more question, those bruises on Joanna's arm? They never really expanded anymore past that bathroom scene. Caused by Alistair?

[C C]

[...]

Wondered this, too - Alistair is a textbook narcissist so perhaps he took the photograph to mark “getting away with it.” What was your take on Alistair’s relationship with his mom?

It wasn't until the prosecutor brought up that Elizabeth hadn't visited him in Scotland (for ten years?) that I even wondered if I had been missing "signs" with regard to that relationship. When his mother suggested or hinted at a single person being involved (perhaps even referencing such as "him"), Alistair was quick to correct her that two individuals could be responsible ("two can keep a secret better than one" or something along that line, if my lousy memory is even half-correct). So his personal nature was apparently as well known to her as to his ex-wife Alexandra. No matter what developed, both remained (surprisingly?) sympathetic to Joanna.

Agreed. I think they had both been 'victims' of Alistair at one point or another. His ex wife still dealt with bouts of abuse from him, like when he stopped over her house to gaslight her. He seemed like a true misogynist in that he hated women, even his own daughter. It appeared like he cared, but for him to put her through that, and his ex wife, his mom, Joanna...it all pointed to misogyny, a loathing of women where the guy pits them against one another. He seemed amused when his ex wife was hurting/jealous. Even his mom appeared uneasy around him. I thought the series covered a lot of ground for just four episodes! Oh...one more question, those bruises on Joanna's arm? They never really expanded anymore past that bathroom scene. Caused by Alistair?

The way the series plays around with non-linear time -- to a mild degree even after the first episode wallowed in it -- makes trying to place some events in order a bit annoying. 

In the 3rd episode, that backtracks to when they first realized Noah was dead, Alistair grabs Joanna as she tries to run in front of the passing truck. When he holds her afterwards, one of his hands might be seen tightly gripping in that area of her arm.

After that (but actually in the prior 2nd episode when they fake the kidnapping that we didn't know was fake yet) Joanna probably has her arms covered up most of the time, except for the scene in the bathroom where Elizabeth notices the bruises, but says nothing.

The expression on her face indicates that mom is probably attributing it to her son's old rough-housing. But when Joanna looks at the bruises, a deliberate cause like that doesn't seem to be what's crossing her mind. (Maybe she's wondering if there's anything about the bruises that could tip their secret.)

But that's my theory: Alistair caused them, but probably not intentionally. It could be a different incident that brought them about, though. As you stated, apparently the story itself never explicitly clarifies the source of the bruises. Their primary purpose seems to be to give Elizabeth an early opportunity to have that ominous reveal on her face about Alistair.