Notice Period Ended but Company Assets with Employee - Can we Relive the employees without collecting the Assets?

Hi, We have 3 resignations of employees who are Senior Resource. There Notice period will end this 30th April 2020. (Lockdown period)
But All assets are with the Employees like - Laptop/Data /ID Card/Simcard. The employees are willing to join other company on 3rd May 2020.
Can the employees Join other company even if our laptop and imp data in laptop is still with them. Can we Relive the employees without collecting the Assets.
What in this case if lockdown gets extended as we are from Pune and chances of extension is more. The Employees have shift to hometown so i am not sure if they can travel. They are not willing to extend Notice period as other company is forcing them to join.

Circumstances are such that travel is impossible.
Relieve them conditionally with clear written acknowledgement of company assets with them.
Ask them to sign their holdings of company assets and endorse it in relief letter.

Send them mail, to return the company owned assets are with them( Laptop/Data /ID Card/Simcard) .
How the employees would join other company on 3rd May 2020, when it is locked down? Call them and discuss, if necessary take an indemnity bond that he is possession of Laptop-make,SL No/Data-details /ID Card/Sim card and shall return within 15 days of lock down enforcement lifted or other wise shall pay the cost decided by the company.

Hi
Thank you for your responses .
As we are from IT services , the data is utmost important to us .. They are also not relieving name their next company . What if they are joining our Competitors , What if any data is shared or leaked .
does only writing on relieving letter will help us in keeping their data safe .
Can i inform them until we dint receive assets , you cannot join any other company . ? can i mention that in letter .

Have you done their F&F settlement of dues. If no, please summon them after lifting of lock down period with the company assets which are in their possession. After clearing all assets by them
you can issue a proper relieving letter alongwith F&F settlement.
It is not advisable to allow them to join other companies alongwith your company assets.
(once they join in other companies, it will be more difficult for you to retrieve your assets from them)
Thanks

No. Full and final settlement is yet to be done .
i have informed them that we will relieve you on the said date . but you cannot join any other company till you dont handover all assets to us.
I hope i have taken a right decision.