Verb る-form + そう
indicates hearsay.
帰るそうだ
'I hear he will go home.'
帰らないそうだ [Negative]
Verb masu stem (i.e. conjunctive form 連用形) + そう
shows information obtained through the senses, observation:
帰りそうだ
'It looks like he will go home.'
帰らなさそう [Negative]
With this, how do you achieve past tense?
For "hearsay", do you say:
帰ったそうだ
' I heard he went home.'
Whilst for "observation", do you say:
帰りそうだった
'It looked like he went home.'