devon and cornwall police
A 50-year-old man has been arrested on suspicion of attempted murder.
It is understood around a dozen families may have been directly affected.
More than a dozen people have been injured.
No injuries were reported.
34-year-old Laura Smallwood collapsed with a neck injury on Wednesday.
The 10-year-old was attacked at a holiday park in Cornwall.
"We are treating this as a single multiple murder investigation.”
A 68-year-old man was arrested in connection to the assault.
The child wasn't wearing socks or shoes and was reportedly "very pale and cold".