Like "The Tyger" poem by William Blake, this one caught my attention to..
The Wild Flower's Song
As I wandered the forest,
The green leaves among,
I heard a Wild Flower
Singing a song.
'I slept in the earth
In the silent night,
I murmured my fears
And I felt delight.
'In the morning I went
As rosy as morn,
To seek for new joy;
But oh! met with scorn.'
I don't know who's my suspect now, but I'll still bet on Bertram as RJ & Van Pelt as his accomplice because RJ needs someone in Jane's team to be his eyes & ears.
And I believe that the poem The Tyger is not the only hint written by William Blake, perhaps clues can be found in several of his writings.