Yes Ravana killed his sister's husband.
As per this chapter of Valmiki Ramayana: Uttar Kanda:
And then going to the city named Asma ruled by the Kalakayas, Ravana() slew the Kalakayas endowed with terriffic striength ;and then with his sword cut of his brother.in law, the husband of Surpanakha, the mighty Vidyujjihva possessed of terriffic strength; as that ...
Previous answers presented excerpts from Shrimad Bhagvat Purana, Padma Purana and Tulasidas Ramcharitamanas. So, I am giving an answer using some other scriptures.
Mentions about Rama leaving Sita is present across several scriptures. I am presenting few among them, assuming the intent of question is (just) about mention of Rama leaving Sita due to the ...
One of the users mentioned Gita Press, which is a good translation. Here is the link:
Another is by Parimal Publication, Delhi. Here is the link:
Rajaji's version is an abridged one. It is good, but it ...
Maa sita's banishment is mentioned in ramcharitamanas as well.
In ramcharitamanas-balkand sag tulsidas says:
बंदउँ अवध पुरी अति पावनि। सरजू सरि कलि कलुष नसावनि॥
प्रनवउँ पुर नर नारि बहोरी। ममता जिन्ह पर प्रभुहि न थोरी॥1॥
सिय निंदक अघ ओघ नसाए। लोक बिसोक बनाइ बसाए॥
बंदउँ कौसल्या दिसि प्राची। कीरति जासु सकल जग माची॥2॥
I reverence the exceedingly holy city of ...
Valmiki and Vyasa were present.
Valmiki was given a boon by Brahma that he will know all the incidents in Ramayana and he can write an epic on it. More details in this answer.
As for Mahabharata, this answer goes in more detail.
In the Srimad Valmiki Ramayana, there are two Rakshasas by the name of Trishiras, one being the commander-in-chief of Khara’s army and the other being Ravana’s son.
1. Trishiras, a chief in Khara’s army
This Trishira is introduced in the 23rd Sarga of the Aranyakanda, while describing the army of Khara that proceeds towards Rama, consequent to Shurpanakha’s ...
If you are looking for an English translation of Critical Edition of Vālmīki Rāmāyaṇa, you can buy:
The Rāmāyaṇa of Vālmīki: An Epic of Ancient India: 6 Volumes in 7 parts
by Robert P. Goldman, Sally J. Sutherland Goldman (mlbd.in)
The Rāmāyaṇa of Vālmīki: An Epic of Ancient India, Volume VII: Uttarakāṇḍa (amazon.com)
You can borrow Vol. 1, Bālakāṇḍa at ...
The questions are
How can Valmiki write Ramayana in 200-500 BC when he was also present
during Ramayana in 9600 BC?
Isn't it a huge discrepancy of about 9000
There are 3 issues involved in the question.
Occurrence of Ramayana at much earlier period
Composing of Ramayana in 200-500 BC
Appearance of Sage Valmiki in both the periods
A piece of ...